Novel carbonylation ligands and their use in the carbonylation of ethylenically unsaturated compounds

ABSTRACT

Novel bidentate ligands of general formula (I) are described Formula (I): R represents a hydrocarbyl aromatic structure. The substituent(s) Yx on the aromatic structure has a total X=1- n  ΣtY X  of atoms other than hydrogen such that  X-1-n ΣtY X  is 4 where n is the total number of substituent(s) Y X  and tY X  represents the total number of atoms other than hydrogen on a particular substituent Y X . The groups X 1 , X 2 , X 3  and X 4  are joined to Q 1  or Q 2  via tertiary carbon atoms to the respective atom Q 1  or Q 2 ; and Q 1  and Q 2  each independently represent phosphorus, arsenic or antimony. A catalyst system and a process for the carbonylation of ethylenically unsaturated compounds utilising the catalyst system is also described.

The present invention relates to the novel bidentate ligands, novelcatalyst systems incorporating such ligands, and their use in thecarbonylation of ethylenically unsaturated compounds.

The carbonylation of ethylenically unsaturated compounds using carbonmonoxide in the presence of an alcohol or water and a catalyst systemcomprising a group 6, 8, 9 or 10 metal, for example, palladium, and aphosphine ligand, for example an alkyl phosphine, cycloalkyl phosphine,aryl phosphine, pyridyl phosphine or bidentate phosphine, has beendescribed in numerous European patents and patent applications, forexample EP-A-0055875, EP-A-04489472, EP-A-0106379, EP-A-0235864,EP-A-0274795, EP-A-0499329, EP-A-0386833, EP-A-0441447, EP-A-0489472,EP-A-0282142, EP-A-0227160, EP-A-0495547 and EP-A-0495548. Inparticular, EP-A-0227160, EP-A-0495547 and EP-A-0495548 disclose thatbidentate phosphine ligands provide catalyst systems which enable highreaction rates to be achieved. C3 alkyl bridges between the phosphorusatoms are exemplified in EP0495548 together with tertiary butylsubstituents on the phosphorus.

WO96/19434 subsequently disclosed that a particular group of bidentatephosphine compounds having an aryl bridge could provide remarkablystable catalysts which require little or no replenishment; that use ofsuch bidentate catalysts leads to reaction rates which are significantlyhigher than those previously disclosed; and that little or no impuritiesare produced at high conversions.

WO 01/68583 discloses rates for the same process as WO 96/19434 whenused for higher alkenes and when in the presence of an externally addedaprotic solvent.

WO 98/42717 discloses a modification to the bidentate phosphines used inEP0495548 wherein one or both phosphorus atoms are incorporated into anoptionally substituted 2-phospha-tricyclo[3.3.1.1{3,7}]decyl group or aderivative thereof in which one or more of the carbon atoms are replacedby heteroatoms (“2-PA” group). The examples include a number ofalkoxycarbonylations of ethene, propene and some higher terminal andinternal olefins.

WO 03/070370 extends the teaching of WO 98/42717 to bidentate phosphineshaving 1, 2 substituted aryl bridges of the type disclosed inWO96/19434. The suitable olefin substrates disclosed include severaltypes having various substituents.

WO 04/103948 describes both the above types of ligand bridges as usefulfor butadiene carbonylation and WO 05/082830 describes a selection of WO04/103948 where the tertiary carbon substituents are different on therespective phosphorus atoms.

It has now been found that by further substituting the aromaticstructure of the aryl bridge of the type described in WO 96/19434, WO01/68583 and WO 03/070370 more stable catalysts and hence higher TON'scan be achieved.

According to the first aspect of the present invention there is provideda novel bidentate ligand of general formula (I)

wherein:A and B each independently represent a lower alkylene linking group;R represents a hydrocarbyl aromatic structure having at least onearomatic ring to which Q¹ and Q² are each linked, via the respectivelinking group, on available adjacent cyclic atoms of the at least onearomatic ring and which is substituted with one or more substituent(s)Y^(X) on one or more further aromatic cyclic atom(s) of the aromaticstructure;wherein the substituent(s) Y^(X) on the aromatic structure has a total^(X=1-n)ΣtY^(X) of atoms other than hydrogen such that ^(X=1-n)ΣtY^(X)is 4, where n is the total number of substituent(s) Y^(X) and tY^(X)represents the total number of atoms other than hydrogen on a particularsubstituent Y^(X);the groups X⁻, X², X³ and X⁴ independently represent univalent radicalsof up to 30 atoms having at least one tertiary carbon atom or X¹ and X²and/or X³ and X⁴ together form a bivalent radical of up to 40 atomshaving at least two tertiary carbon atoms wherein each said univalent orbivalent radical is joined via said at least one or two tertiary carbonatoms respectively to the respective atom Q¹ or Q²; and

Q¹ and Q² each independently represent phosphorus, arsenic or antimony.

The above novel bidentate ligands have been found to have surprisinglyimproved stability in carbonylation reactions. Typically, the turnovernumber (TON) (moles of metal/moles of product) for the carbonylationreaction, especially, hydroxy- or alkoxy-carbonylation is close to orgreater than that for 1,3-bis(di-t-butylphosphino)propane reacted underthe same conditions, more preferably, greater than1,2-bis(di-t-butylphosphinomethyl)benzene reacted under the sameconditions. Preferably, such conditions are in continuous reactions butbatch reactions will also benefit.

Therefore, according to a second aspect of the present invention thereis provided a process for the carbonylation of ethylenically unsaturatedcompounds comprising reacting said compound with carbon monoxide in thepresence of a source of hydroxyl groups and of a catalyst system, thecatalyst system obtainable by combining:

(a) a metal of Group 8, 9 or 10 or a compound thereof: and(b) a bidentate ligand of general formula (I)

wherein:A and B each independently represent lower alkylene linking groups;R represents a hydrocarbyl aromatic structure having at least onearomatic ring to which Q¹ and Q² are each linked, via the respectivelinking group, on available adjacent cyclic atoms of the at least onearomatic ring and which is substituted with one or more substituent(s)Y^(X) on one or more further aromatic cyclic atom(s) of the aromaticstructure;wherein the substituent(s) Y^(X) on the aromatic structure has a total^(X=1-n)ΣtY^(X) of atoms other than hydrogen such that ^(X=1-n)ΣtY^(X)is 4, where n is the total number of substituent(s) Y^(X) and tY^(X)represents the total number of atoms other than hydrogen on a particularsubstituent Y^(X);the groups X⁻, X², X³ and X⁴ independently represent univalent radicalsof up to 30 atoms having at least one tertiary carbon atom or X¹ and X²and/or X³ and X⁴ together form a bivalent radical of up to 40 atomshaving at least two tertiary carbon atoms wherein each said univalent orbivalent radical is joined via said at least one or two tertiary carbonatoms respectively to the respective atom Q¹ or Q²; andQ¹ and Q² each independently represent phosphorus, arsenic or antimony;and, optionally, a source of anions.

Typically, when there is more than one substituent Y^(X) hereinafteralso referred to as simply Y, any two may be located on the same ordifferent aromatic cyclic atoms of the aromatic structure. Preferably,there are ≦10 Y groups ie n is 1 to 10, more preferably there are 1-6 Ygroups, most preferably 1-4 Y groups on the aromatic structure and,especially, 1, 2 or 3 substituent Y groups on the aromatic structure.The substituted cyclic aromatic atoms may be carbon or hetero but arepreferably carbon.

Preferably, ^(X=1-n)ΣtY^(X) is 1 between 4-100, more preferably, 4-60,most preferably, 4-20, especially 4-12.

Preferably, when there is one substituent Y, Y represents a group whichis at least as sterically hindering as phenyl and when there are two ormore substituents Y they are each as sterically hindering as phenyland/or combine to form a group which is more sterically hindering thanphenyl.

By sterically hindering herein, whether in the context of the groupsR¹-R¹² described hereinafter or the substituent Y, we mean the term asreadily understood by those skilled in the art but for the avoidance ofany doubt, the term more sterically hindering than phenyl can be takento mean having a lower degree of substitution (DS) than PH₂Ph when PH₂Y(representing the group Y) is reacted with Ni(O)(CO)₄ in eightfoldexcess according to the conditions below. Similarly, references to moresterically hindering than t-butyl can be taken as references to DSvalues compared with PH₂t-Bu etc. If two Y groups are being compared andPHY¹ is not more sterically hindered than the reference then PHY¹Y²should be compared with the reference. Similarly, if three Y groups arebeing compared and PHY¹ or PHY¹Y² are not already determined to be moresterically hindered than the standard then PY¹Y²Y³ should be compared.If there are more than three Y groups they should be taken to be moresterically hindered than t-butyl.

Steric hindrance in the context of the invention herein is discussed onpage 14 et seq of “Homogenous Transition Metal Catalysis—A Gentle Art”,by C. Masters, published by Chapman and Hall 1981.

Tolman (“Phosphorus Ligand Exchange Equilibria on Zerovalent Nickel. ADominant Role for Steric Effects”, Journal of American Chemical Society,92, 1970, 2956-2965) has concluded that the property of the ligandswhich primarily determines the stability of the Ni(O) complexes is theirsize rather than their electronic character.

To determine the relative steric hindrance of a group Y the method ofTolman to determine DS may be used on the phosphorus analogue of thegroup to be determined as set out above.

Toluene solutions of Ni(CO)₄ were treated with an eightfold excess ofphosphorus ligand; substitution of CO by ligand was followed by means ofthe carbonyl stretching vibrations in the infrared spectrum. Thesolutions were equilibriated by heating in sealed tubes for 64 hr at100°. Further heating at 100° for an additional 74 hrs did notsignificantly change the spectra. The frequencies and intensities of thecarbonyl stretching bands in the spectra of the equilibriated solutionsare then determined. The degree of substitution can be estimatedsemiquantitatively from the relative intensities and the assumption thatthe extinction coefficients of the bands are all of the same order ofmagnitude. For example, in the case of P(C₆H₂₂)₃ the A₁ band of Ni(CO)₃Land the B₁ band of Ni(CO)₂L₂ are of about the same intensity, so thatthe degree of substitution is estimated at 1.5. If this experiment failsto distinguish the respective ligands then the diphenyl phosphorus PPh₂Hor di-t-butyl phosphorus should be compared to the PY₂H equivalent asthe case may be. Still further, if this also fails to distinguish theligands then the PPh₃ or P(^(t)Bu)₃ ligand should be compared to PY₃, asthe case may be. Such further experimentation may be required with smallligands which fully substitute the Ni(CO)₄ complex.

The group Y may also be defined by reference to its cone angle which canbe defined in the context of the invention as the apex angle of acylindrical cone centred at the midpoint of the aromatic ring. Bymidpoint is meant a point in the plane of the ring which is equidistantfrom the cyclic ring atoms.

Preferably, the cone angle of the at least one group Y or the sum of thecone angles of two or more Y groups is at least 100, more preferably, atleast 200, most preferably, at least 30°. Cone angle should be measuredaccording to the method of Tolman {C. A. Tolman Chem. Rev. 77, (1977),313-348} except that the apex angle of the cone is now centred at themidpoint of the aromatic ring. This modified use of Tolman cone angleshas been used in other systems to measure steric effects such as thosein cyclopentadienyl zirconium ethene polymerisation catalysts (Journalof Molecular Catalysis: Chemical 188, (2002), 105-113).

The substituents Y are selected to be of the appropriate size to providesteric hindrance with respect to the active site between the Q⁴ and Q²atoms. However, it is not known whether the substituent is preventingthe metal leaving, directing its incoming pathway, generally providing amore stable catalytic confirmation, or acting otherwise.

A particularly preferred ligand is found when Y represents —SR⁴⁰R⁴¹R⁴²wherein S represents Si, C, N, S, O or aryl and R⁴⁰R⁴¹R⁴² are as definedhereinafter. Preferably each Y and/or combination of two or more Ygroups is at least as sterically hindering as t-butyl.

More preferably, when there is only one substituent Y, it is at least assterically hindering as t-butyl whereas where there are two or moresubstituents Y, they are each at least as sterically hindering as phenyland at least as sterically hindering as t-butyl if considered as asingle group.

Preferably, when S is aryl, R⁴⁰, R⁴⁴ and R⁴² are independently hydrogen,alkyl, —BQ³-X³(X⁴) (wherein B, X³ and X⁴ are as defined herein and Q³ isdefined as Q⁴ or Q² above), phosphorus, aryl, arylene, alkaryl,arylenalkyl, alkenyl, alkynyl, het, hetero, halo, cyano, nitro, —OR¹⁹,OC(O)R²⁰, C(O)R²¹, C(O)OR²², —N(R²³)R²⁴, —C(O)N(R²⁵) R²⁶, —SR²⁹,—C(O)SR³⁰, —C(S)N(R²⁷)R²⁸, —CF₃, —SiR⁷¹R⁷²R⁷³ or alkylphosphorus.

R¹⁹-R³⁰ referred to herein may independently be generally selected fromhydrogen, unsubstituted or substituted aryl or unsubstituted orsubstituted alkyl, in addition R²¹ may be nitro, halo, amino or thio.

Preferably, when S is Si, C, N, S or O, R⁴⁰, R⁴¹ and R⁴² areindependently hydrogen, alkyl, phosphorus, aryl, arylene, alkaryl,aralkyl, arylenalkyl, alkenyl, alkynyl, het, hetero, halo, cyano, nitro,—OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²², —N(R²³)R²⁴, —C(O)N(R²⁵)R²⁶, —SR²⁹,—C(O)SR³⁰, —C(S)N(R²⁻⁷)R²⁸, —CF₃, —SiR⁷¹R⁷²R⁷³, or alkylphosphoruswherein at least one of R⁴⁰-R⁴² is not hydrogen and wherein R¹⁹-R³⁰ areas defined herein; and R⁷¹-R⁷³ are defined as R⁴⁰-R⁴² but are preferablyC₁-C₄ alkyl or phenyl.

Preferably, S is Si, C or aryl. However, N, S or O may also be preferredas one or more of the Y groups in combined or in the case of multiple Ygroups. For the avoidance of doubt, as oxygen or sulphur can bebivalent, R⁴⁰-R⁴² can also be lone pairs.

Preferably, in addition to group Y, the aromatic structure may beunsubstituted or, when possible be further substituted with groupsselected from Y (on the non-aromatic cyclic atoms), alkyl, aryl,arylene, alkaryl, aralkyl, arylenalkyl, alkenyl, alkynyl, het, hetero,halo, cyano, nitro, —OR¹⁹, —OC(O)R²⁰, —C(O)R²¹, —C(O)OR²², —N(R²³)R²⁴,—C(O)N(R²⁵)R²⁶, —SR²⁹, —C(O)SR³⁰, —C(S)N(R²⁻⁷) R²⁸, —CF₃, —SiR²¹R⁷²R²³,or alkylphosphorus wherein R¹⁹-R³⁰ are as defined herein and in the caseof Y or a group fulfilling the definition of Y of the first aspect theattachment is to a non-cyclic aromatic atom of the aromatic structure;and R⁷¹-R⁷³ are defined as R⁴⁰-R⁴² but are preferably C₁-C₄ alkyl orphenyl. In addition, the at least one aromatic ring can be part of ametallocene complex, for instance when R is a cyclopentadienyl orindenyl anion it may form part of a metal complex such as ferrocenyl,ruthenocyl, molybdenocenyl or indenyl equivalents.

Such complexes should be considered as aromatic structures within thecontext of the present invention so that, when they include more thanone aromatic ring, the substituent(s) Y^(X) may be on the same aromaticring as that to which the Q¹ and Q² atoms are linked or a furtheraromatic ring of the structure. For instance, in the case of ametallocene, the substituent Y^(X) may be on any one or more rings ofthe metallocene structure and this may be the same or a different ringto which Q¹ and Q² are linked.

Suitable metallocene type ligands which may be substituted with a groupY as defined herein will be known to the skilled person and areextensively defined in WO 04/024322. A particularly preferred Ysubstituent for such aromatic anions is when S is Si.

In general, however, when S is aryl, the aryl may be furtherunsubstituted or substituted with, in addition to R⁴⁰, R⁴¹, R⁴², any ofthe further substituents defined for the aromatic structure above.

More preferred Y substituents in the present invention may be selectedfrom t-alkyl or t-alkyl,aryl such as -t-butyl or 2-phenylprop-2-yl,—SiMe₃, -phenyl, alkylphenyl-, phenylalkyl- or phosphinoalkyl—such asphosphinomethyl.

Preferably, when S is Si or C and one or more of R⁴⁰-R⁴² are hydrogen,at least one of R⁴⁰-R⁴² should be sufficiently bulky to give therequired steric hindrance and such groups are preferably phosphorus,phosphinoalkyl-, a tertiary carbon bearing group such as -t-butyl,-aryl, -alkaryl, -aralkyl or tertiary silyl.

Preferably, the hydrocarbyl aromatic structure has, includingsubstituents, from 5 up to 70 cyclic atoms, more preferably, 5 to 40cyclic atoms, most preferably, 5-22 cyclic atoms, especially 5 or 6cyclic atoms, if not a metallocene complex.

Preferably, the aromatic hydrocarbyl structure may be monocyclic orpolycyclic. The cyclic aromatic atoms may be carbon or hetero, whereinreferences to hetero herein are references to sulphur, oxygen and/ornitrogen. However, it is preferred that the Q¹ and Q² atoms are linkedto available adjacent cyclic carbon atoms of the at least one aromaticring. Typically, when the cyclic hydrocarbyl structure is polycylic itis preferably bicyclic or tricyclic. The further cycles in the aromaticstructure may or may not themselves be aromatic and aromatic structureshould be understood accordingly. A non-aromatic cyclic ring(s) asdefined herein may include unsaturated bonds. By cyclic atom is meant anatom which forms part of a cyclic skeleton.

Preferably, the bridging group —R(Y^(X))_(n), whether furthersubstituted or otherwise preferably comprises less than 200 atoms, morepreferably, less than 150 atoms, more preferably, less than 100 atoms.

By the term one further aromatic cyclic atom of the aromatic structureis meant any further aromatic cyclic atom in the aromatic structurewhich is not an available adjacent cyclic atom of the at least onearomatic ring to which the Q¹ or Q² atoms are linked, via the linkinggroup.

Preferably, the immediately adjacent cyclic atoms on either side of thesaid available adjacent cyclic atoms are preferably not substituted. Asan example, an aromatic phenyl ring joined to a Q¹ atom via position 1on the ring and joined to a Q² atom via position 2 on the ring haspreferably one or more said further aromatic cyclic atoms substituted atring position 4 and/or 5 and the two immediately adjacent cyclic atomsto the said available adjacent cyclic atoms not substituted at positions3 and 6. However, this is only a preferred substituent arrangement andsubstitution at ring positions 3 and 6, for example, is possible.

The term aromatic ring means that the at least one ring to which the Q²and Q² atom are linked via B & A respectively is aromatic, and aromaticshould preferably be interpreted broadly to include not only a phenyl,cyclopentadienyl anion, pyrollyl, pyridinyl, type structures but otherrings with aromaticity such as that found in any ring with delocalisedPi electrons able to move freely in the said ring.

Preferred aromatic rings have 5 or 6 atoms in the ring but rings with4n+2 μl electrons are also possible such as [14] annulene, [18]annulene, etc

The aromatic hydrocarbyl structure may be selected from 4 and/or 5t-alkylbenzene-1,2-diyl, 4,5-diphenyl-benzene-1,2-diyl, 4 and/or5-phenyl-benzene-1,2-diyl, 4,5-di-t-butyl-benzene-1,2-diyl, 4 or5-t-butylbenzene-1,2-diyl, 2, 3, 4 and/or 5t-alkyl-naphthalene-8,9-diyl, 1H-inden-5,6-diyl, 1, 2 and/or 3methyl-1H-inden-5,6-diyl, 4,7 methano-1H-indene-1,2-diyl, 1, 2 and/or3-dimethyl-1H-inden 5,6-diyls, 1,3-bis(trimethylsilyl)-isobenzofuran5,6-diyl, 4-(trimethylsilyl) benzene-1,2 diyl, 4-phosphinomethylbenzene-1,2 diyl, 4-(2′-phenylprop-2′-yl)benzene-1,2 diyl,4-dimethylsilylbenzene-1,2diyl, 4-di-t-butyl,methylsilylbenzene-1,2diyl, 4-(t-butyldimethylsilyl)-benzene-1,2diyl,4-t-butylsilyl-benzene-1,2diyl, 4-(tri-t-butylsilyl)-benzene-1,2diyl,4-(2′-tert-butylprop-2′-yl)benzene-1,2 diyl, 4-(2′,2′,3′,4′,4′pentamethyl-pent-3′-yl)-benzene-1,2diyl,4-(2′,2′,4′,4′-tetramethyl,3′-t-butyl-pent-3′-yl)-benzene-1,2 diyl,4-(or 1′)t-alkylferrocene-1,2-diyl, 4,5-diphenyl-ferrocene-1,2-diyl,4-(or 1′)phenyl-ferrocene-1,2-diyl, 4,5-di-t-butyl-ferrocene-1,2-diyl,4-(or 1′)t-butylferrocene-1,2-diyl, 4-(or 1′)(trimethylsilyl)ferrocene-1,2 diyl, 4-(or 1′)phosphinomethyl ferrocene-1,2 diyl, 4-(or1′)(2′-phenylprop-2′-yl) ferrocene 1,2 diyl, 4-(or1′)dimethylsilylferrocene-1,2diyl, 4-(or 1′)di-t-butyl,methylsilylferrocene-1,2diyl, 4-(or 1′)(t-butyldimethylsilyl)-ferrocene-1,2diyl,4-(or 1′)t-butylsilyl-ferrocene-1,2diyl, 4-(or1′)(tri-t-butylsilyl)-ferrocene-1,2diyl, 4-(or1′)(2′-tert-butylprop-2′-yl)ferrocene-1,2 diyl, 4-(or 1′)(2′,2′,3′,4′,4′pentamethyl-pent-3′-yl)-ferrocene-1,2diyl, 4-(or1′)(2′,2′,4′,4′-tetramethyl,3′-t-butyl-pent-3′-yl)-ferrocene-1,2 diyl.

In the structures herein, where there is more than one stereisomericform possible, all such stereoisomers are intended.

As mentioned above, in some embodiments, there may be two or more ofsaid Y and/or non-Y substituents on further aromatic cyclic atoms of thearomatic structure. Optionally, the said two or more substituents may,especially when themselves on neighbouring cyclic aromatic atoms,combine to form a further ring structure such as a cycloaliphatic ringstructure.

Such cycloaliphatic ring structures may be saturated or unsaturated,bridged or unbridged, substituted with alkyl, Y groups as definedherein, aryl, arylene, alkaryl, aralkyl, arylenalkyl, alkenyl, alkynyl,het, hetero, halo, cyano, nitro, —OR¹⁹, —OC(O)R²⁰, —C(O) R²¹—C(O)OR²²,—N(R²³)R²⁴, —C(O)N(R²⁸)R²⁸, —SR²⁹, —C(O)SR³³, —C(S)N(R²⁷) R²⁸, —CF₃,—SiR⁷¹R⁷²R⁷³, or phosphinoalkyl wherein, when present, at least one ofR⁴⁰-R⁴² is not hydrogen and wherein R¹⁹-R³⁰ are as defined herein; andR⁷¹-R⁷³ are defined as R⁴⁰-R⁴² but are preferably C₁-C₄ alkyl or phenyland/or be interrupted by one or more (preferably less than a total of 4)oxygen, nitrogen, sulphur, silicon atoms or by silano or dialkyl silicongroups or mixtures thereof.

Examples of such structures include piperidine, pyridine, morpholine,cyclohexane, cycloheptane, cyclooctane, cyclononane, furan, dioxane,alkyl substituted DIOP, 2-alkyl substituted 1,3 dioxane, cyclopentanone,cyclohexanone, cyclopentene, cyclohexene, cyclohexadiene, 1,4 dithiane,piperizine, pyrollidine, thiomorpholine, cyclohexenone,bicyclo[4.2.0]octane, bicyclo[4.3.0]nonane, adamantane, tetrahydropyran,dihydropyran, tetrahydrothiopyran, tetrahydro-furan-2-one, deltavalerolactone, gamma-butyrolactone, glutaric anhydride,dihydroimidazole, triazacyclononane, triazacyclodecane, thiazolidine,hexahydro-1H-indene (5,6 diyl), octahydro-4,7 methano-indene (1,2 diyl)and tetrahydro-1H-indene (5,6 diyl) all of which may be unsubstituted orsubstituted as defined for aryl herein.

However, whether forming combined groups or otherwise, it is preferredthat the immediate adjacent aromatic cyclic atoms, on either side of thesaid available adjacent cyclic atoms to which Q¹ and Q² are linked, viathe said linking group, are un-substituted and preferable substitutionis elsewhere on the at least one aromatic ring or elsewhere in thearomatic structure when the aromatic structure comprises more than onearomatic ring and the preferred position of combined Y substituentsshould be understood accordingly.

Typically, the group X² represents CR¹(R²) (R³), X² represents CR⁴ (R⁵)(R⁶), X³ represents CR⁷(R⁸) (R⁹) and X⁴ represents CR¹⁰ (R¹¹)(R¹²)wherein R² to R²² represent alkyl, aryl or het.

Particularly preferred is when the organic groups R¹-R³, R⁴-R⁶, R⁷-R⁹and/or R¹⁰-R¹² or, alternatively, R⁴-R⁶ and/or R⁷-R¹² when associatedwith their respective tertiary carbon atom(s) form composite groupswhich are at least as sterically hindering as t-butyl(s).

The steric groups may be cyclic, part-cyclic or acyclic. When cyclic orpart cyclic, the group may be substituted or unsubstituted or saturatedor unsaturated. The cyclic or part cyclic groups may preferably contain,including the tertiary carbon atom(s), from C₄-C₃₄, more preferablyC₈-C₂₄, most preferably C₁₀-C₂₀ carbon atoms in the cyclic structure.The cyclic structure may be substituted by one or more substituentsselected from halo, cyano, nitro, OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²²,NR²³R²⁴, C(O)NR²⁵R²⁶, SR²⁹, R²⁸, C(O)SR³⁰, C(S)NR²⁷R²⁸, aryl or Het,wherein R¹⁹ to R³⁰ each independently represent hydrogen, aryl or alkyl,and/or be interrupted by one or more oxygen or sulphur atoms, or bysilano or dialkylsilicon groups.

In particular, when cyclic, X¹, X², X³ and/or X⁴ may representcongressyl, norbornyl, 1-norbornadienyl or adamantyl, or X¹ and X²together with Q² to which they are attached form an optionallysubstituted 2-Q²-tricyclo[3.3.1.1{3,7}]decyl group or derivativethereof, or X¹ and X² together with Q² to which they are attached form aring system of formula 1a

Similarly, X³ and X⁴ together with Q¹ to which they are attached mayform an optionally substituted 2-Q¹-tricyclo[3.3.1.1{3,7}]decyl group orderivative thereof, or X³ and X⁴ together with Q¹ to which they areattached may form a ring system of formula 1b

Alternatively, one or more of the groups X¹, X², X³ and/or X⁴ mayrepresent a solid phase to which the ligand is attached.

Particularly preferred is when X¹, X², X³ and X⁴ or X¹ and X² togetherwith its respective Q² atom and X³ and X⁴ together with its respectiveQ¹ atom are the same or when X¹ and X³ are the same whilst X² and X⁴ aredifferent but the same as each other.

In preferred embodiments, R¹ to R¹² each independently represent alkyl,aryl, or Het;

R¹⁹ to R³³ each independently represent hydrogen, alkyl, aryl or Het;R⁴⁹ and R⁵⁴, when present, each independently represent hydrogen, alkylor aryl;R⁵⁰ to R⁵³, when present, each independently represent alkyl, aryl orHet;YY¹ and YY², when present, each independently represent oxygen, sulfuror N—R⁵⁵, wherein R⁵⁵ represents hydrogen, alkyl or aryl.

Preferably, R¹ to R¹² each independently represent alkyl or aryl. Morepreferably, R¹ to R¹² each independently represent C₁ to C₆ alkyl, C₁-C₆alkyl phenyl (wherein the phenyl group is optionally substituted as arylas defined herein) or phenyl (wherein the phenyl group is optionallysubstituted as aryl as defined herein). Even more preferably, R¹ to R¹²each independently represent C₁ to C₆ alkyl, which is optionallysubstituted as alkyl as defined herein. Most preferably, R¹ to R¹² eachrepresent non-substituted C₁ to C₆ alkyl such as methyl, ethyl,n-propyl, iso-propyl, n-butyl, iso-butyl, tert-butyl, pentyl, hexyl andcyclohexyl, especially methyl.

In a particularly preferred embodiment of the present invention R¹, R⁴,R⁷ and R¹⁰ each represent the same alkyl, aryl or Het moiety as definedherein, R², R⁵, R⁸ and R¹¹ each represent the same alkyl, aryl or Hetmoiety as defined herein, and R³, R⁶, R⁹ and R¹² each represent the samealkyl, aryl or Het moiety as defined herein. More preferably R¹, R⁴, R⁷and R¹⁰ each represent the same C₁-C₆ alkyl, particularlynon-substituted C₁-C₆ alkyl, such as methyl, ethyl, n-propyl,iso-propyl, n-butyl, iso-butyl, tert-butyl, pentyl, hexyl or cyclohexyl;R², R⁵, R⁸ and R¹¹ each independently represent the same C₁-C₆ alkyl asdefined above; and R³, R⁶, R⁹ and R⁹² each independently represent thesame C₁-C₆ alkyl as defined above. For example: R¹, R⁴, R⁷ and R¹⁰ eachrepresent methyl; R², R⁵, R⁸ and R¹¹ each represent ethyl; and, R³, R⁶,R⁹ and R¹² each represent n-butyl or n-pentyl.

In an especially preferred embodiment of the present invention each R¹to R⁹² group represents the same alkyl, aryl, or Het moiety as definedherein. Preferably, when alkyl groups, each R¹ to R⁹² represents thesame C₁ to C₆ alkyl group, particularly non-substituted C₁-C₆ alkyl,such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl,tert-butyl, pentyl, hexyl and cyclohexyl. More preferably, each R¹ toR¹² represents methyl or tert-butyl, most preferably, methyl.

The term “lower alkylene” which A and B represent in a compound offormula 1, when used herein, includes C₀-C₁₀ or C₁ to C₁₀ groups which,in the latter case, can be bonded at two places on the group to therebyconnect the group Q¹ or Q² to the R group, and, in the latter case, isotherwise defined in the same way as “alkyl” below. Nevertheless, in thelatter case, methylene is most preferred. In the former case, by C₀ ismeant that the group Q¹ or Q² is connected directly to the R group andthere is no C₁-C₁₀ lower alkylene group and in this case only one of Aand B is a C₁-C₁₀ lower alkylene. In any case, when one of the groups Aor B is C₀ then the other group cannot be C₀ and must be a C₁-C₁₀ groupas defined herein and, therefore, at least one of A and B is a C₁-C₁₀“lower alkylene” group.

The term “alkyl” when used herein, means C₁ to C₁₀ alkyl and includesmethyl, ethyl, ethenyl, propyl, propenyl butyl, butenyl, pentyl,pentenyl, hexyl, hexenyl and heptyl groups.

Unless otherwise specified, alkyl groups may, when there is a sufficientnumber of carbon atoms, be linear or branched (particularly preferredbranched groups include t-butyl and isopropyl), be saturated orunsaturated, be cyclic, acyclic or part cyclic/acyclic, beunsubstituted, substituted or terminated by one or more substituentsselected from halo, cyano, nitro, OR¹⁹, OC(O)R²⁹, C(O)R²¹, C(O)OR²²,NR²³R²⁴, C(O)NR²⁵R²⁶, SR²⁹, C(O)SR⁹⁰, C(S)NR²⁷R²⁸, unsubstituted orsubstituted aryl, or unsubstituted or substituted Het, wherein R¹⁹ toR²⁰ each independently represent hydrogen, halo, unsubstituted orsubstituted aryl or unsubstituted or substituted alkyl, or, in the caseof R²¹, halo, nitro, cyano and amino and/or be interrupted by one ormore (preferably less than 4) oxygen, sulphur, silicon atoms, or bysilano or dialkylsilicon groups, or mixtures thereof.

The term “Ar” or “aryl” when used herein, includes five-to-ten-membered,preferably five to eight membered, carbocyclic aromatic or pseudoaromatic groups, such as phenyl, cyclopentadienyl and indenyl anions andnaphthyl, which groups may be unsubstituted or substituted with one ormore substituents selected from unsubstituted or substituted aryl, alkyl(which group may itself be unsubstituted or substituted or terminated asdefined herein), Het (which group may itself be unsubstituted orsubstituted or terminated as defined herein), halo, cyano, nitro, OR¹⁹,OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁶R²⁶, SR²⁹, C(O)SR³⁰ orC(S)NR²⁷R²⁸ wherein R¹⁹ to R³⁰ each independently represent hydrogen,unsubstituted or substituted aryl or alkyl (which alkyl group may itselfbe unsubstituted or substituted or terminated as defined herein), or, inthe case of R²¹, halo, nitro, cyano or amino.

The term “alkenyl” when used herein, means C₂ to C₁₀ alkenyl andincludes ethenyl, propenyl, butenyl, pentenyl, and hexenyl groups.Unless otherwise specified, alkenyl groups may, when there is asufficient number of carbon atoms, be linear or branched, be saturatedor unsaturated, be cyclic, acyclic or part cyclic/acyclic, beunsubstituted, substituted or terminated by one or more substituentsselected from halo, cyano, nitro, OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²²,NR²³R²⁴, C(O)NR²⁶R²⁶, SR²⁹, C(O)SR³⁰, C(S)NR²⁷R²⁸, unsubstituted orsubstituted aryl, or unsubstituted or substituted Het, wherein R¹⁹ toR³⁰ are defined as for alkyl above and/or be interrupted by one or more(preferably less than 4) oxygen, sulphur, silicon atoms, or by silano ordialkylsilicon groups, or mixtures thereof.

The term “alkynyl” when used herein, means C₂ to C₁₀ alkynyl andincludes ethynyl, propynyl, butynyl, pentynyl, and hexynyl groups.Unless otherwise specified, alkynyl groups may, when there is asufficient number of carbon atoms, be linear or branched, be saturatedor unsaturated, be cyclic, acyclic or part cyclic/acyclic, beunsubstituted, substituted or terminated by one or more substituentsselected from halo, cyano, nitro, OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²²,NR²³R²⁴, C(O)NR²⁶R²⁶, SR²⁹, C(O)SR³⁰, C(S)NR²⁷R²⁸, unsubstituted orsubstituted aryl, or unsubstituted or substituted Het, wherein R¹⁹ toR³⁰ are defined as for alkyl above and/or be interrupted by one or more(preferably less than 4) oxygen, sulphur, silicon atoms, or by silano ordialkylsilicon groups, or mixtures thereof.

The terms “alkyl”, “aralkyl”, “alkaryl”, “arylenealkyl” or the likeshould, in the absence of information to the contrary, be taken to be inaccordance with the above definition of “alkyl” as far as the alkyl oralk portion of the group is concerned.

The above Ar or aryl groups may be attached by one or more covalentbonds but references to “arylene” or “arylenealkyl” or the like hereinshould be understood as two covalent bond attachment but otherwise bedefined as Ar or aryl above as far as the arylene portion of the groupis concerned. References to “alkaryl”, “aralkyl” or the like should betaken as references to Ar or aryl above as far as the Ar or aryl portionof the group is concerned.

Halo groups with which the above-mentioned groups may be substituted orterminated include fluoro, chloro, bromo and iodo.

The term “Het”, when used herein, includes four- to twelve-membered,preferably four- to ten-membered ring systems, which rings contain oneor more heteroatoms selected from nitrogen, oxygen, sulfur and mixturesthereof, and which rings contain no, one or more double bonds or may benon-aromatic, partly aromatic or wholly aromatic in character. The ringsystems may be monocyclic, bicyclic or fused. Each “Het” groupidentified herein may be unsubstituted or substituted by one or moresubstituents selected from halo, cyano, nitro, oxo, alkyl (which alkylgroup may itself be unsubstituted or substituted or terminated asdefined herein) —OR¹⁹, —OC(O)R²⁰, —C(O)R²¹, —C(O)OR²²,—N(R²³)^(R24),C(O)N(R²⁵) R²⁶, —SR²⁹, —C(O)SR³⁰ or —C(S)N(R²⁷) R²⁸whereinR¹⁹ to R³⁰ each independently represent hydrogen, unsubstituted orsubstituted aryl or alkyl (which alkyl group itself may be unsubstitutedor substituted or terminated as defined herein) or, in the case of R²¹,halo, nitro, amino or cyano. The term “Het” thus includes groups such asoptionally substituted azetidinyl, pyrrolidinyl, imidazolyl, indolyl,furanyl, oxazolyl, isoxazolyl, oxadiazolyl, thiazolyl, thiadiazolyl,triazolyl, oxatriazolyl, thiatriazolyl, pyridazinyl, morpholinyl,pyrimidinyl, pyrazinyl, quinolinyl, isoquinolinyl, piperidinyl,pyrazolyl and piperazinyl. Substitution at Het may be at a carbon atomof the Het ring or, where appropriate, at one or more of theheteroatoms.

“Het” groups may also be in the form of an N oxide.

The term hetero as mentioned herein means nitrogen, oxygen, sulfur ormixtures thereof.

The adamantyl, congressyl, norbornyl or 1-norborndienyl group mayoptionally comprise, besides hydrogen atoms, one or more substituentsselected from alkyl, —OR¹⁹, —OC(O)R²⁹, halo, nitro, —C(O)R²¹, —C(O)OR²²,cyano, aryl, —N(R²³)R²⁴, —C(O)N(R²⁵)R²⁶, —C(S)(R²⁷) R²⁹, —SR²⁹,—C(O)SR³⁰—P(R⁵⁶)R⁵⁷, —PO(R⁵⁸) (R⁵⁹), —PO₃H₂, —PO(OR⁶⁰)(OR⁶¹), or—SO₃R⁶², wherein R¹⁹-R³⁰, alkyl, halo, cyano and aryl are as definedherein and R⁵⁶ to R⁶² each independently represent hydrogen, alkyl, arylor Het.

Suitably, when the adamantyl, congressyl, norbornyl or 1-norborndienylgroup is substituted with one or more substituents as defined above,highly preferred substituents include unsubstituted C₁ to C₈ alkyl,—OR¹⁹, —OC(O)R²⁹, phenyl, —C(O)OR²², fluoro, —SO₃H, —N(R²³)R²⁴,—P(R⁵⁶)_(R) ⁵⁷, —C(O)N(R²⁵)R²⁶ and —PO(R⁵⁸)(R⁵⁹), —CF₃, wherein R¹⁹represents hydrogen, unsubstituted C₁-C₈ alkyl or phenyl, R²⁰, R²², R²³,R²⁴, R²⁵, R²⁶ each independently represent hydrogen or unsubstitutedC₁-C₈ alkyl, R⁵⁶ to R⁵⁹ each independently represent unsubstituted C₁-C₈alkyl or phenyl. In a particularly preferred embodiment the substituentsare C₁ to C₈ alkyl, more preferably, methyl such as found in 1,3dimethyl adamantyl.

Suitably, the adamantyl, congressyl, norbornyl or 1-norborndienyl groupmay comprise, besides hydrogen atoms, up to 10 substituents as definedabove, preferably up to 5 substituents as defined above, more preferablyup to 3 substituents as defined above. Suitably, when the adamantyl,congressyl, norbornyl or 1-norborndienyl group comprises, besideshydrogen atoms, one or more substituents as defined herein, preferablyeach substituent is identical. Preferred substituents are unsubstitutedC₁-C₈ alkyl and trifluoromethyl, particularly unsubstituted C₁-C₈ alkylsuch as methyl. A highly preferred adamantyl, congressyl, norbornyl or1-norborndienyl group comprises hydrogen atoms only i.e. the adamantylcongressyl, norbornyl or 1-norborndienyl group is not substituted.

Preferably, when more than one adamantyl, congressyl, norbornyl or1-norborndienyl group is present in a compound of formula 1, each suchgroup is identical.

The 2-Q²(or Q²)-tricyclo[3.3.1.1.{3,7}]decyl group (referred tohereinafter as a 2-meta-adamantyl group for convenience wherein2-meta-adamantyl is a reference to Q¹ or Q² being an arsenic, antimonyor phosphorus atom i.e. 2-arsa-adamantyl and/or 2-stiba-adamantyl and/or2-phospha-adamantyl, preferably, 2-phospha-adamantyl) may optionallycomprise, beside hydrogen atoms, one or more substituents. Suitablesubstituents include those substituents as defined herein in respect ofthe adamantyl group. Highly preferred substituents include alkyl,particularly unsubstituted C₁-C₈ alkyl, especially methyl,trifluoromethyl, —OR¹⁹ wherein R²⁹ is as defined herein particularlyunsubstituted C₁-C₈ alkyl or aryl, and 4-dodecylphenyl. When the2-meta-adamantyl group includes more than one substituent, preferablyeach substituent is identical.

Preferably, the 2-meta-adamantyl group is substituted on one or more ofthe 1, 3, 5 or 7 positions with a substituent as defined herein. Morepreferably, the 2-meta-adamantyl group is substituted on each of the 1,3 and 5 positions. Suitably, such an arrangement means the Q atom of the2-meta-adamantyl group is bonded to carbon atoms in the adamantylskeleton having no hydrogen atoms. Most preferably, the 2-meta-adamantylgroup is substituted on each of the 1, 3, 5 and 7 positions. When the2-meta-adamantyl group includes more than 1 substituent preferably eachsubstituent is identical. Especially preferred substituents areunsubstituted C₁-C₈ alkyl and haloakyls, particularly unsubstitutedC₁-C₈ alkyl such as methyl and fluorinated C₁-C₈ alkyl such astrifluoromethyl.

Preferably, 2-meta-adamantyl represents unsubstituted 2-meta-adamantylor 2-meta-adamantyl substituted with one or more unsubstituted C₁-C₈alkyl substituents, or a combination thereof.

Preferably, the 2-meta-adamantyl group includes additional heteroatoms,other than the 2-Q atom, in the 2-meta-adamantyl skeleton. Suitableadditional heteroatoms include oxygen and sulphur atoms, especiallyoxygen atoms. More preferably, the 2-meta-adamantyl group includes oneor more additional heteroatoms in the 6, 9 and 10 positions. Even morepreferably, the 2-meta-adamantyl group includes an additional heteroatomin each of the 6, 9 and 10 positions. Most preferably, when the2-meta-adamantyl group includes two or more additional heteroatoms inthe 2-meta-adamantyl skeleton, each of the additional heteroatoms areidentical. Preferably, the 2-meta-adamantyl includes one or more oxygenatoms in the 2-meta-adamantyl skeleton. An especially preferred2-meta-adamantyl group, which may optionally be substituted with one ormore substituents as defined herein, includes an oxygen atom in each ofthe 6, 9 and 10 positions of the 2-meta-adamantyl skeleton.

Highly preferred 2-meta-adamantyl groups as defined herein include2-phospha-1,3,5,7-tetramethyl-6,9,10-trioxadamantyl,2-phospha-1,3,5-trimethyl-6,9,10-trioxadamantyl,2-phospha-1,3,5,7-tetra(trifluoromethyl)-6,9,10-trioxadamantyl group,and 2-phospha-1,3,5-tri(trifluoromethyl)-6,9,10-trioxadamantyl group.Most preferably, the 2-phospha-adamantyl is selected from2-phospha-1,3,5,7-tetramethyl-6,9,10-trioxadamantyl group or2-phospha-1,3,5,-trimethyl-6,9,10-trioxadamantyl group.

Preferably, when more than one 2-meta-adamantyl group is present in acompound of formula 1, each 2-meta-adamantyl group is identical.However, it can also be advantageous if asymmetric ligands are preparedand if such ligands include a 2-meta-adamantyl group incorporating theQ¹ atom then other groups can be found on the Q² atom or vice versa.

The 2-meta-adamantyl group may be prepared by methods well known tothose skilled in the art. Suitably, certain 2-phospha-adamantylcompounds are obtainable from Cytec Canada Inc, Canada. Likewisecorresponding 2-meta-adamantyl compounds of formula 1etc may be obtainedfrom the same supplier or prepared by analogous methods.

Preferred embodiments of the present invention include those wherein:

X³ represents CR⁷(R⁸) (R⁹), X⁴ represents CR¹⁰(R¹¹)(R¹²), X² representsCR¹ (Fe) (R³) and X² represents CR⁴ (R⁵) (R⁶);X³ represents CR⁷(R⁸) (R⁹), X⁴ represents CR¹⁰(R¹¹)(R¹²), and X¹ and X¹together with Q² to which they are attached form a 2-phospha-adamantylgroup;X³ represents CR⁷(R⁸) (R⁹), X⁴ represents CR¹⁰ (R¹¹)(R¹²); and X¹ and X¹together with Q² to which they are attached form a ring system offormula 1a;

X³ represents CR⁷(R⁸) (R⁹), X⁴ represents adamantyl, and X¹ and X²together with Q² to which they are attached form a 2-phospha-adamantylgroup;X³ represents CR⁷(R⁸) (R⁹), X⁴ represents adamantyl and X¹ and X²together with Q² to which they are attached form a ring system offormula 1a;

X³ represents CR⁷(R⁸) (R⁹), X⁴ represents adamantyl, X¹ represents CR¹(R²) (R³) and X² represents CR⁴ (R⁵) (R⁶) ;X³ represents CR⁷(R⁸) (R⁹), X⁴ represents congressyl, and X¹ and X²together with Q² to which they are attached form a 2-phospha-adamantylgroup;X³ represents CR⁷(R⁸)(R⁹), X⁴ represents congressyl, X¹ represents CR¹(R²) (R³) and X² represents CR⁴ (R⁵) (R⁶);X³ and X⁴ independently represent adamantyl, and X² and X² together withQ² to which they are attached form a 2-phospha-adamantyl group;X³ and X⁴ independently represent adamantyl, and X² and X² together withQ² to which they are attached form a ring system of formula 1a;

X³ and X⁴ independently represent adamantyl, X¹ represents CR¹ (R²) (R³)and X² represents CR⁴ (R⁵) (R⁶) ;X², X², X³ and X⁴ represent adamantyl;X³ and X⁴ together with Q² to which they are attached may form a ringsystem of formula 1b

and X² and X² together with Q² to which they are attached form a ringsystem of formula 1a;

X³ and X⁴ independently represent congressyl, and X¹ and X² togetherwith Q² to which they are attached form a 2-phospha-adamantyl group;X³ and X⁴ together with Q¹ to which they are attached may form a ringsystem of formula 1b

and X¹ and X² together with Q², to which they are attached form a2-phospha-adamantyl group;X³ and X⁴ independently represent congressyl, and X¹ represents CR¹ (R²)(R³) and X² represents CR⁴ (R⁵) (R⁶) ;X³ and X⁴ together with Q¹ to which they are attached may form a ringsystem of formula 1b

X¹ represents CR¹ (R²)(R³) and X² represents CR⁴(R⁵) (R⁶);X³ and X⁴ together with Q² to which they are attached form a2-phospha-adamantyl group, and X² and X² together with Q² to which theyare attached form a 2-phospha-adamantyl group

Highly preferred embodiments of the present invention include thosewherein:

X³ represents CR²(R⁸) (R⁹), X⁴ represents CR¹⁰(R¹¹)(R¹²), X¹ representsCR¹(R²) (R³) and X² represents CR⁴(R⁵) (R⁶); especially where R¹-R¹² aremethyl.

Preferably in a compound of formula 1, X³ is identical to X⁴ and/or X²is identical to X².

Particularly preferred combinations in the present invention includethose wherein:—

-   (1) X³ represents CR²(R⁸) (R⁹), X₄ represents CR¹⁰ (R¹¹) (R¹²), X¹    represents CR¹ (R²) (R³) and X² represents CR⁴(R⁵) (R⁶) ;    -   A and B are the same and represent —CH₂—;    -   Q² and Q² both represent phosphorus linked to the R group at        ring positions 1 and 2;    -   R represents 4-(trimethylsilyl)-benzene-1,2-diyl-   (2) X³ represents CR²(R⁸) (R⁹), X⁴ represents CR¹⁰ (R¹¹) (R¹²), X¹    represents CR¹ (R²) (R³) and X² represents CR⁴(R⁵) (R⁶) ;    -   A and B are the same and represent —CH₂—;    -   Q¹ and Q² both represent phosphorus linked to the R group at        ring positions 1 and 2;    -   R represents 4-t-butyl-benzene-1,2-diyl.-   (3) X³ and X⁴ together with Q¹ to which they are attached form a    2-phospha-adamantyl group, and, X¹ and X² together with Q² to which    they are attached form a 2-phospha-adamantyl group;    -   A and B are the same and represent —CH₂—;    -   Q¹ and Q² both represent phosphorus linked to the R group at        ring positions 1 and 2;    -   R represents 4-(trimethylsilyl)-benzene-1,2-diyl.-   (4) X¹, X², X³ and X⁴ represent adamantyl;    -   A and B are the same and represent —CH₂—;    -   Q¹ and Q² both represent phosphorus linked to the R group at        ring positions 1 and 2;    -   R represents 4-(trimethylsilyl)-benzene-1,2-diyl.

Preferably, in the compound of formula 1, A and B each independentlyrepresents C₁ to C₆ alkylene which is optionally substituted as definedherein, for example with alkyl groups. Preferably, the lower alkylenegroups which A and B represent are non-substituted. Particularlypreferred alkylene which A and B may independently represent are —CH₂—or —C₂H₄—. Most preferably, each of A and B represent the same alkyleneas defined herein, particularly —CH₂—. Alternatively, one of A or B isC₀ ie Q² or Q¹ is connected directly to the group R and the other Qgroup is not connected directly to the group R and is a C₁ to C₆alkylene, preferably —CH₂— or —C₂H₄—, most preferably, —CH₂.

Still further preferred compounds of formula 1include those wherein:

R¹ to R¹² are alkyl and are the same and preferably, each represents C₁to C₆ alkyl, particularly methyl.

Especially preferred specific compounds of formula 1include thosewherein:

each R¹ to R¹² is the same and represents methyl;A and B are the same and represent —CH₂—;R represents 4-t-butyl-benzene-1,2-diyl or4(trimethylsilyl)-benzene-1,2-diyl.

Examples of suitable bidentate ligands are1,2-bis(di-t-butylphosphinomethyl)-4,5-diphenyl benzene;1,2-bis(di-t-butylphosphinomethyl)-4-phenylbenzene;1,2-bis(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1,2-bis(di-t-butylphosphinomethyl)-4-(trimethylsilyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-diphenylbenzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-phenylbenzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-bis-(trimethylsilyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-(trimethylsilyl)benzene;1,2-bis(di-adamantylphosphinomethyl)-4,5 diphenylbenzene;1,2-bis(di-adamantylphosphinomethyl)-4-phenyl benzene;1,2-bis(di-adamantylphosphinomethyl)-4,5 bis-(trimethylsilyl)benzene;1,2-bis(di-adamantylphosphinomethyl)-4-(trimethylsilyl)benzene; 1-(P,Padamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-diphenylbenzene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-phenylbenzene; 1-(P,Padamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-1-(di-t-butylphosphinomethyl)-4,5-diphenylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-phenylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl) 2(di-t-butylphosphinomethyl)-4-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-phenylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(trimethylsilyl)benzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylbenzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-phenylbenzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(trimethylsilyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-diphenylbenzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-phenylbenzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-bis-(trimethylsilyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-diphenylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-phenylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-phenylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(trimethylsilyl)benzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-diphenylbenzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-phenylbenzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-bis-(trimethylsilyl)benzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(trimethylsilyl)benzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-diphenylbenzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-phenylbenzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-bis-(trimethylsilyl)benzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(trimethylsilyl)benzene;1,2-bis(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1,2-bis(di-t-butylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1,2-bis(di-t-butylphosphinomethyl)-4,5-di-t-butyl benzene;1,2-bis(di-t-butylphosphinomethyl)-4-t-butylbenzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-(2′-phenylprop-2′-yl)benzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-(di-t-butyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-t-butylbenzene;1,2-bis(di-adamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1,2-bis(di-adamantylphosphinomethyl)-4-(2′-phenylprop-2′-yl) benzene;1,2-bis(di-adamantylphosphinomethyl)-4,5-(di-t-butyl)benzene;1,2-bis(di-adamantylphosphinomethyl)-4-t-butyl benzene; 1-(P,Padamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-(di-t-butyl)benzene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-t-butylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-(di-t-butyl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-t-butylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-t-butylbenzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)benzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-t-butylbenzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(2′-phenylprop-2′-yl)benzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-(di-t-butyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-t-butylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-(di-t-butyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-t-butylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-t-butylbenzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(2′-phenylprop-2′-yl)benzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-(di-t-butyl)benzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-t-butylbenzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(2′-phenylprop-2′-yl)benzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-(di-t-butyl)benzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-t-butylbenzene and1-(8-phosphinomethyl-1,3,5,7-tetramethyl-2,4,6-trioxatricyclo{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-5-(trimethylsilyl)benzene.

Examples of suitable bidentate ferrocene type ligands are1,2-bis(di-t-butylphosphinomethyl)-4,5-diphenyl ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4-(or 1′)phenylferrocene;1,2-bis(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl) ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4-(or 1′)(trimethylsilyl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-diphenylferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)4-(or 1′)phenylferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-bis-(trimethylsilyl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)4-(or 1′)(trimethylsilyl)ferrocene;1,2-bis(di-adamantylphosphinomethyl)-4,5 diphenylferrocene;1,2-bis(di-adamantylphosphinomethyl)-4-(or 1′)phenyl ferrocene;1,2-bis(di-adamantylphosphinomethyl)-4,5 bis-(trimethylsilyl)ferrocene;1,2-bis(di-adamantylphosphinomethyl)-4-(or 1′)(trimethylsilyl)ferrocene; 1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-diphenylferrocene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(or 1′)phenylferrocene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)(trimethylsilyl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-diphenylferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)phenyl ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl) 2(di-t-butylphosphinomethyl)-4-(or 1′)(trimethylsilyl) ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(or1′)phenyl ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(trimethylsilyl) ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(or1′)phenyl ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(trimethylsilyl) ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-diphenylferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(or1′)phenyl ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-bis-(trimethylsilyl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(or1′)(trimethylsilyl) ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-diphenylferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)phenyl ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)(trimethylsilyl) ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(or1′)phenyl ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(trimethylsilyl) ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-diphenylferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)phenyl ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-bis-(trimethylsilyl)ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)(trimethylsilyl) ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-diphenylferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)phenyl ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-bis-(trimethylsilyl)ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)(trimethylsilyl) ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl)ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4,5-di-t-butyl ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4-(or 1′)t-butylferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-(or1′)(2′-phenylprop-2′-yl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-(di-t-butyl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-(or1′)t-butylferrocene;1,2-bis(di-adamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene; 1,2-bis(di-adamantylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1,2-bis(di-adamantylphosphinomethyl)-4,5-(di-t-butyl) ferrocene;1,2-bis(di-adamantylphosphinomethyl)-4-(or 1′)t-butyl ferrocene; 1-(P,Padamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl)ferrocene; 1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)t-butylferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)t-butyl ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(or1′)t-butyl ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(or1′)t-butyl ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-(di-t-butyl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(or1′)t-butyl ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)t-butyl ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(or1′)_(t)-butyl ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-(di-t-butyl)ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)t-butyl ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-(di-t-butyl)ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)t-butyl ferrocene.

The invention also extends to a modification of all the above examplesof suitable bidentate ligands and suitable bidentate ferrocene typeligands wherein one of the methylene linking groups attached to thearomatic ring is removed so that the respective phosphorus atom isattached directly to the ring representing R. In these modifiedexamples, when one methylene has been removed, the other methylene grouplinking the other phosphorus atom is still present so that a C₃ bridgeconnects the two phosphorus atoms representing Q¹ and Q² in each exampleabove.

Selected structures of ligands of the invention include:—

-   1,2-bis(di-tert-butylphosphinomethyl)-3,6-diphenyl-4,5-dimethyl    benzene

-   1,2bis(di-tert-butyl(phosphinomethyl)-4,5-diphenyl benzene

-   1,2-bis(di-tert-butylphospinomethyl)-1′-trimethylsilyl ferrocene

-   1,2-bis(di-tert-butylphospinomethyl)-1′-tert-butyl ferrocene

-   5,6-bis(di-tert-butylphosphinomethyl)-1,3-bis-trimethylsilyl-1,3-dihydroisobenzofuran

-   1,2-bis(di-tert-butylphosphinomethyl)-3,6-diphenyl benzene

-   1,2-bis(di-tert-butylphospinomethyl)-4-trimethylsilyl ferrocene

-   1,2 bis(di-tert-butyl(phosphinomethyl))-4,5-di(4′-tert butyl    phenyl)benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4-trimethylsilyl benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4-(tert-butyldimethylsilyl)benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4,5-bis(trimethylsilyl)benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4-tert-butyl benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4,5-di-tert-butyl benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4-(tri-tert-butylmethyl)benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4-(tri-tert-butylsilyl)benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4-(2′-phenylprop-2′-yl)benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4-phenyl benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-3,6-dimethyl-4,5-diphenyl    benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-3,4,5,6-tetraphenyl benzene

-   4-(1-{3,4-Bis-[(di-tert-butyl-phosphanyl)-methyl]-phenyl}-1-methyl-ethyl)-benzoyl    chloride

-   1,2-bis(di-tert-butyl(phosphinomethyl)-4-(4′-chlorocarbonyl-phenyl)benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4-(phosphinomethyl)benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4-(2′-naphthylprop-2′-yl)    benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4-(3′,4′-bis(di-tert-butyl(phosphinomethyl))phenyl)benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-3-(2′,3′-bis(di-tert-butyl(phosphinomethyl))phenyl)benzene

-   1,2-bis(di-tert-butyl(phosphinomethyl))-4-tertbutyl-5-(2′-tertbutyl-4′,5′-bis(di-tert-butyl(phosphinomethyl))phenyl)benzene

In the above example, structures of ligands of general formula (I), oneor more of the X¹-X⁴ tertiary carbon bearing groups, t-butyl, attachedto the Q¹ and/or Q² group phosphorus may be replaced by a suitablealternative. Preferred alternatives are adamantyl, 1,3 dimethyladamantyl, congressyl, norbornyl or 1-norbondienyl, or X¹ and X²together and/or X³ and X⁴ together form together with the phosphorus a2-phospha-tricyclo[3.3.1.1{3,7} decyl group such as2-phospha-1,3,5,7-tetramethyl-6,9,10-trioxadamantyl or2-phospha-1,3,5-trimethyl-6,9,10-trioxadamantyl. In most embodiments, itis preferred that the X¹-X⁴ groups or the combined X¹/X² and X³/X⁴groups are the same but it may also be advantageous to use differentgroups to produce asymmetry around the active site in these selectedligands and generally in this invention.

Similarly, in all the above example structures of ligands of generalformula (I) including the t-butyl alternatives, one of the methylenelinking groups representing A or B in formula (I), may as analternative, be removed so that the respective phosphorus atom,representing Q¹ and Q² is attached directly to the aromatic ringrepresenting R. In these modified example structures, the othermethylene group linking the other phosphorus atom is still present sothat a C₃ bridge connects the two respective phosphorus atomsrepresenting Q¹ and Q² in each example structure.

Preferably, Q² is phosphorus and preferably, independently, phosphorus.

Preferably, the bidentate ligand is a bidentate phosphine, arsine orstibine ligand, preferably, a phosphine ligand.

For the avoidance of doubt, references to Group 8, 9 or 10 metals hereinshould be taken to include Groups 8, 9 and 10 in the modern periodictable nomenclature. By the term “Group 8, 9 or 10” we preferably selectmetals such as Ru, Rh, Os, Ir, Pt and Pd. Preferably, the metals areselected from Ru, Pt and Pd. More preferably, the metal is Pd.

Suitable compounds of such Group 8, 9 or 10 metals include salts of suchmetals with, or compounds comprising weakly coordinated anions derivedfrom, nitric acid; sulphuric acid; lower alkanoic (up to C₁₂) acids suchas acetic acid and propionic acid; sulphonic acids such as methanesulphonic acid, chlorosulphonic acid, fluorosulphonic acid,trifluoromethane sulphonic acid, benzene sulphonic acid, naphthalenesulphonic acid, toluene sulphonic acid, e.g. p-toluene sulphonic acid,t-butyl sulphonic acid, and 2-hydroxypropane sulphonic acid; sulphonatedion exchange resins (including low acid level sulphonic resins) perhalicacid such as perchloric acid; halogenated carboxylic acids such astrichloroacetic acid and trifluoroacetic acid; orthophosphoric acid;phosphonic acids such as benzenephosphonic acid; and acids derived frominteractions between Lewis acids and Broensted acids. Other sourceswhich may provide suitable anions include the optionally halogenatedtetraphenyl borate derivatives, e.g. perfluorotetraphenyl borate.Additionally, zero valent palladium complexes particularly those withlabile ligands, e.g. triphenylphosphine or alkenes such asdibenzylideneacetone or styrene or tri(dibenzylideneacetone)dipalladiummay be used. The above anions may be introduced directly as a compoundof the metal but should preferably be introduced to the catalyst systemindependently of the metal or metal compound.

The anion may be derived from or introduced as one or more of an acidhaving a pKa measured in dilute aqueous solution at 18° C. of less than6, more preferably, less than 5, most preferably less than 4, a saltwith a cation that does not interfere with the reaction, e.g. metalsalts or largely organic salts such as alkyl ammonium, and a precursor,such as an ester, that can break down under reaction conditions togenerate the anion in situ. Suitable acids and salts include the acidsand salts listed supra.

Particularly preferred acid promoters for an alkoxycarbonylation are thesulfonic acids, including the sulfonated ion exchange resins, and thecarboxylic acids listed supra. The low level acid ion exchange resinsthat may be used preferably provide a level of SO₃H/Pd ratio in thereaction of less than 35 mol/mol, more preferably less than 25 mol/mol,most preferably less than 15 mol/mol. Typical ranges for the SO₃Hconcentration provided by the resin are in the range 1-40 mol/mol Pd,more typically, 2-30 mol/mol Pd, most typically 3-20 mol/mol Pd.

Generally the anion(s) can be selected which is appropriate to thereaction. Certain ethylenically unsaturated compounds may be moresensitive to the pKa of the acid of the anion than others and conditionsand solvent can be varied as appropriate within the skill of the personin the art For instance, in butadiene carbonylation the pKa of the acidof the anion should be greater than 2 in dilute aqueous solution at 18°C., more preferably, having a pka between 2 and 5.

In a carbonylation reaction, the quantity of anion present is notcritical to the catalytic behaviour of the catalyst system. The molarratio of anion to Group 8, 9 or 10 metal or compound may be from 1:1 to10000:1, preferably from 10:1 to 2000:1 and particularly from 100:1 to1000:1. Where the anion is provided by an acid and salt, the relativeproportion of the acid and salt is not critical. However, where an anionis provided by acid or partially provided by acid the ratio of acid togroup 8, 9 or 10 metal is preferably, in the same ratios as the anion tometal or compound above. By H⁺is meant the amount of active acidic sitesso that a mole of monobasic acid would have 1 mole of H⁺whereas a moleof dibasic acid would have 2 moles of H⁺and tribasic acids etc should beinterpreted accordingly. Similarly, by C²⁺ is meant moles of metalhaving a 2⁺ cationic charge so that for M⁺ions the ratio of the metalcation should be adjusted accordingly. For example, an M⁺cation shouldbe taken as having 0.5 moles of C²⁺ per mole of M⁺.

In an alkoxycarbonylation reaction, preferably, the ratio of bidentateligand to acid is at least 1:2 mol/mol(H⁺) and preferably, the ratio ofbidentate ligand to group 8, 9 or 10 metal is at least 1:1 mol/mol(C²⁺).Preferably, the ligand is in excess of metal mol/mol(C²¹and preferablyin excess of a ratio of 1:2 mol/mol(H⁺) with the acid. Excess ligand isadvantageous as the ligand itself may act as a base to buffer the acidlevels in the reaction and prevent degradation of substrate. On theother hand the presence of acid activates the reaction mix and improvesthe overall rate of reaction.

In an hydroxycarbonylation reaction, preferably, the ratio of bidentateligand to acid is at least 1:2 mol/mol(H⁺) and preferably, the ratio ofbidentate ligand to group 8, 9 or 10 metal is at least 1:1 mol/mol(C²⁺).Preferably, the ligand is in excess of metal mol/mol(C²⁺). Excess ligandmay be advantageous as the ligand itself may act as a base to buffer theacid levels in the reaction and prevent degradation of substrate. On theother hand the presence of acid activates the reaction mix and improvesthe overall rate of reaction.

As mentioned, the catalyst system of the present invention may be usedhomogeneously or heterogeneously. Preferably, the catalyst system isused homogeneously.

Suitably, the process of the invention may be used to catalyse thecarbonylation of ethylenically unsaturated compounds in the presence ofcarbon monoxide and a hydroxyl group containing compound and,optionally, a source of anions. The ligands of the invention yield asurprisingly high TON in carbonylation reactions such as ethylene,propylene, 1,3-butadiene, pentenenitrile, and octene carbonylation.Consequently, the commercial viability of a carbonylation process willbe increased by employing the process of the invention.

Advantageously, use of the catalyst system of the present invention inthe carbonylation of ethylenically unsaturated compounds etc also givesgood rates especially for alkoxy- and hydroxycarbonylation.

References to ethylenically unsaturated compounds herein should be takento include any one or more unsaturated C—C bond(s) in a compound such asthose found in alkenes, alkynes, conjugated and unconjugated dienes,functional alkenes etc.

Suitable ethylenically unsaturated compounds for the invention areethylenically unsaturated compounds having from 2 to 50 carbon atoms permolecule, or mixtures thereof. Suitable ethylenically unsaturatedcompounds may have one or more isolated or conjugated unsaturated bondsper molecule.

Preferred are compounds having from 2 to 20 carbon atoms, or mixturesthereof, yet more preferred are compounds having at most 18 carbonatoms, yet more at most 16 carbon atoms, again more preferred compoundshave at most 10 carbon atoms. The ethylenically unsaturated compound mayfurther comprise functional groups or heteroatoms, such as nitrogen,sulphur or oxide. Examples include carboxylic acids, esters or nitrilesas functional groups. In a preferred group of processes, theethylenically unsaturated compound is an olefin or a mixture of olefins.Suitable ethylenically unsaturated compounds include acetylene, methylacetylene, propyl acetylene, 1,3-butadiene, ethylene, propylene,butylene, isobutylene, pentenes, pentene nitriles, alkyl pentenoatessuch as methyl 3-pentenoates, pentene acids (such as 2- and 3-pentenoicacid), heptenes, vinyl esters such as vinyl acetate, octenes, dodecenes.

Particularly preferred ethylenically unsaturated compounds are ethylene,vinyl acetate, 1,3-butadiene, alkyl pentenoates, pentenenitriles,pentene acids (such as 3 pentenoic acid), acetylene, heptenes, butylene,octenes, dodecenes and propylene.

Especially preferred ethylenically unsaturated compounds are ethylene,propylene, heptenes, octenes, dodecenes, vinyl acetate, 1,3-butadieneand pentene nitriles.

Still further, it is possible to carbonylate mixtures of alkenescontaining internal double bonds and/or branched alkenes with saturatedhydrocarbons. Examples are raffinate 1, raffinate 2 and other mixedstreams derived from a cracker, or mixed streams derived from alkenedimerisation (butene dimerisation is one specific example) and fischertropsch reactions.

References to vinyl esters herein include references to substituted orunsubstituted vinyl ester of formula (IV):

R⁶²—C(O)OCR⁶³═CR⁶⁴R⁶⁵

wherein R⁶² may be selected from hydrogen, alkyl, aryl, Het, halo,cyano, nitro, OR¹⁹, OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵R²⁶,C(S)R²⁷R²⁸, SR²⁹, C(O)SR³⁰ wherein R⁴⁹-R³⁰ are as defined herein.

Preferably, R⁶² is selected from hydrogen, alkyl, phenyl or alkylphenyl,more preferably, hydrogen, phenyl, C₁-C₆ alkylphenyl or C₁-C₆ alkyl,such as methyl, ethyl, propyl, butyl, pentyl and hexyl, even morepreferably, C₁-C₆ alkyl, especially methyl.

Preferably, R⁶³-R⁶⁵ each independently represents hydrogen, alkyl, arylor Het as defined herein. Most preferably, R⁶³-R⁶⁵ independentlyrepresents hydrogen.

Optionally, however, reference to ethylenically unsaturated compoundsherein can exclude vinyl esters including vinyl acetate.

Where a compound of a formula herein (e.g. formulas I or IV) contains analkenyl group or a cycloalkyl moiety as defined, cis (E) and trans (Z)isomerism may also occur. The present invention includes the individualstereoisomers of the compounds of any of the formulas defined hereinand, where appropriate, the individual tautomeric forms thereof,together with mixtures thereof. Separation of diastereoisomers or cisand trans isomers may be achieved by conventional techniques, e.g. byfractional crystallisation, chromatography or H.P.L.C. of astereoisomeric mixture of a compound one of the formulas or a suitablesalt or derivative thereof. An individual enantiomer of a compound ofone of the formulas may also be prepared from a corresponding opticallypure intermediate or by resolution, such as by H.P.L.C. of thecorresponding racemate using a suitable chiral support or by fractionalcrystallisation of the diastereoisomeric salts formed by reaction of thecorresponding racemate with a suitable optically active acid or base, asappropriate.

All stereoisomers are included within the scope of the process of theinvention.

It will be appreciated by those skilled in the art that the compounds offormula (I) may function as ligands that coordinate with the Group 8, 9or 10 metal or compound thereof to form the compounds for use in theinvention. Typically, the Group 8, 9 or 10 metal or compound thereofcoordinates to the one or more phosphorus, arsenic and/or antimony atomsof the compound of formula (I).

As mentioned above, the present invention provides a process for thecarbonylation of ethylenically unsaturated compound comprisingcontacting an ethylenically unsaturated compound with carbon monoxideand a source of hydroxyl groups such as water or an alkanol in thepresence of a catalyst compound as defined in the present invention.

Suitably, the source of hydroxyl groups includes an organic moleculehaving an hydroxyl functional group. Preferably, the organic moleculehaving a hydroxyl functional group may be branched or linear, andcomprises an alkanol, particularly a C₁-C₃₀ alkanol, including arylalkanols, which may be optionally substituted with one or moresubstituents selected from alkyl, aryl, Het, halo, cyano, nitro, OR¹⁹,OC(O)R²⁰, C(O)R²¹, C(O)OR²², NR²³R²⁴, C(O)NR²⁵R²⁶, C(S)R²⁷R²⁸, SR²⁹ orC(O)SR³⁰ as defined herein. Highly preferred alkanols are C₁-C₈ alkanolssuch as methanol, ethanol, propanol, iso-propanol, iso-butanol, t-butylalcohol, n-butanol, phenol and chlorocapryl alcohol. Although themonoalkanols are most preferred, poly-alkanols, preferably, selectedfrom di-octa ols such as diols, triols, tetra-ols and sugars may also beutilised. Typically, such polyalkanols are selected from 1,2-ethanediol,1,3-propanediol, glycerol, 1,2,4 butanetriol,2-(hydroxymethyl)-1,3-propanediol, 1,2,6 trihydroxyhexane,pentaerythritol, 1,1,1 tri(hydroxymethyl)ethane, nannose, sorbase,galactose and other sugars. Preferred sugars include sucrose, fructoseand glucose. Especially preferred alkanols are methanol and ethanol. Themost preferred alkanol is methanol.

The amount of alcohol is not critical. Generally, amounts are used inexcess of the amount of substrate to be carbonylated. Thus the alcoholmay serve as the reaction solvent as well, although, if desired,separate solvents may also be used.

It will be appreciated that the end product of the reaction isdetermined at least in part by the source of alkanol used. For instance,use of methanol produces the corresponding methyl ester. Conversely, useof water produces the corresponding acids. Accordingly, the inventionprovides a convenient way of adding the group —C(O)O C₁-C₃₀ alkyl oraryl or —C(O)OH across the ethylenically unsaturated bond.

In the process according to the second aspect of the present invention,the carbon monoxide may be used in pure form or diluted with an inertgas such as nitrogen, carbon dioxide or a noble gas such as argon. Smallamounts of hydrogen, typically less than 5% by volume, may also bepresent.

The ratio (volume/volume) of ethylenically unsaturated compounds tohydroxyl group source in a liquid phase reaction medium may vary betweenwide limits and suitably lies in the range of 1:0.1 to 1:10, preferablyfrom between 2:1 to 1:2 and up to a large excess of alkanol or waterwhen the latter is also the reaction solvent such as up to a 100:1excess of alkanol or water. However, if the ethylenically unsaturatedcompound is a gas at the reaction temperature it may be present at lowerlevels in the liquid phase reaction medium such as at a ratio tohydroxyl group source of 1:20,000 to 1:10 more preferably, 1:10,000 to1:50, most preferably, 1:5000 to 1:500

The amount of the catalyst of the invention used in the carbonylationprocess is not critical. Good results may be obtained when, preferably,the amount of Group 8, 9 or 10 metal is in the range 10⁻⁷ to 10⁻¹, morepreferably, 10⁻⁶ to 10⁻², most preferably, 10⁻⁵ to 10⁻² moles per moleof ethylenically unsaturated compound in the liquid phase carbonylationreaction medium.

Suitably, although non-essential to the invention, the carbonylation ofethylenically unsaturated compound as defined herein may be performed inone or more aprotic solvents.

Suitable solvents include ketones, such as for examplemethylbutylketone; ethers, such as for example anisole (methyl phenylether), 2,5,8-trioxanonane (diglyme), diethyl ether, dimethyl ether,tetrahydrofuran, diphenylether, diisopropylether and the dimethyletherof di-ethylene-glycol; esters, such as for example methylacetate,dimethyladipate methyl benzoate, dimethyl phthalate and butyrolactone;amides, such as for example dimethylacetamide, N-methylpyrrolidone anddimethyl formamide; sulfoxides and sulphones, such as for exampledimethylsulphoxide, di-isopropylsulphone, sulfolane(tetrahydrothiophene-2,2-dioxide), 2-methylsulfolane, diethyl sulphone,tetrahydrothiophene 1,1-dioxide and 2-methyl-4-ethylsulfolane; aromaticcompounds, including halo variants of such compounds e.g. benzene,toluene, ethyl benzene o-xylene, m-xylene, p-xylene, chlorobenzene,o-dichlorobenzene, m-dichlorobenzene: alkanes, including halo variantsof such compounds egg, hexane, heptane, 2,2,3-trimethylpentane,methylene chloride and carbon tetrachloride; nitriles e.g. benzonitrileand acetonitrile.

Very suitable are aprotic solvents having a dielectric constant that isbelow a value of 50, more preferably in the range of 3 to 8, at 298.15 Kand 1×10⁵Nm⁻². In the present context, the dielectric constant for agiven solvent is used in its normal meaning of representing the ratio ofthe capacity of a condenser with that substance as dielectric to thecapacity of the same condenser with a vacuum for dielectric. Values forthe dielectric constants of common organic liquids can be found ingeneral reference books, such as the Handbook of Chemistry and Physics,76^(th) edition, edited by David R. Lide et al, and published by CRCpress in 1995, and are usually quoted for a temperature of about 20° C.or 25° C., i.e. about 293.15 k or 298.15 K, and atmospheric pressure,i.e. about 1×10⁵Nm⁻², or can readily be converted to that temperatureand pressure using the conversion factors quoted. If no literature datafor a particular compound is available, the dielectric constant may bereadily measured using established physico-chemical methods.

For example, the dielectric constant of anisole is 4.3 (at 294.2 K), ofdiethyl ether is 4.3 (at 293.2 K), of sulfolane is 43.4 (at 303.2 K), ofmethylpentanoate is 5.0 (at 293.2 K), of diphenylether is 3.7 (at 283.2K), of dimethyladipate is 6.8 (at 293.2 K), of tetrahydrofuran is 7.5(at 295.2 K), of methylnonanoate is 3.9 (at 293.2 K). A preferredaprotic solvent is anisole.

In the presence of an alkanol, an aprotic solvent will be generated bythe reaction as the ester carbonylation product of the ethylenicallyunsaturated compound, carbon monoxide and the alkanol is an aproticsolvent.

The process may be carried out in an excess of aprotic solvent, i.e. ata ratio (v/v) of aprotic solvent to alkanol of at least 1:1. Preferably,this ratio ranges from 1:1 to 10:1 and more preferably from 1:1 to 5:1.Most preferably the ratio (v/v) ranges from 1.5:1 to 3:1.

Despite the foregoing it is preferred that the reaction is carried outin the absence of any external added aprotic solvent i.e. in the absenceof an aprotic solvent not generated by the reaction itself.

During hydroxycarbonylation, the presence of a protic solvent is alsopreferred. The protic solvent may include a carboxylic acid or analcohol. Mixtures of the aprotic and protic solvents may also beemployed.

Hydrogen may be added to the carbonylation reaction to improve reactionrate. Suitable levels of hydrogen when utilised may be in the ratio ofbetween 0.1 and 20% vol/vol of the carbon monoxide, more preferably,1-20% vol/vol of the carbon monoxide, more preferably, 2-15% vol/vol ofthe carbon monoxide, most preferably 3-10% vol/vol of carbon monoxide.

The catalyst compounds of the present invention may act as a“heterogeneous” catalyst or a “homogeneous” catalyst, preferably, ahomogenous catalyst.

By the term “homogeneous” catalyst we mean a catalyst, i.e. a compoundof the invention, which is not supported but is simply admixed or formedin-situ with the reactants of the carbonylation reaction (e.g. theethylenically unsaturated compound, the hydroxyl containing compound andcarbon monoxide), preferably in a suitable solvent as described herein.

By the term “heterogeneous” catalyst we mean a catalyst, i.e. thecompound of the invention, which is carried on a support.

Thus according to a further aspect, the present invention provides aprocess for the carbonylation of ethylenically unsaturated compounds asdefined herein wherein the process is carried out with the catalystcomprising a support, preferably an insoluble support.

Preferably, the support comprises a polymer such as a polyolefin,polystyrene or polystyrene copolymer such as a divinylbenzene copolymeror other suitable polymers or copolymers known to those skilled in theart; a silicon derivative such as a functionalised silica, a silicone ora silicone rubber; or other porous particulate material such as forexample inorganic oxides and inorganic chlorides.

Preferably the support material is porous silica which has a surfacearea in the range of from 10 to 700 m²/g, a total pore volume in therange of from 0.1 to 4.0 cc/g and an average particle size in the rangeof from 10 to 500 μm. More preferably, the surface area is in the rangeof from 50 to 500 m²/g, the pore volume is in the range of from 0.5 to2.5 cc/g and the average particle size is in the range of from 20 to 200μm. Most desirably the surface area is in the range of from 100 to 400m²/g, the pore volume is in the range of from 0.8 to 3.0 cc/g and theaverage particle size is in the range of from 30 to 100 μm. The averagepore size of typical porous support materials is in the range of from 10to 1000 Å. Preferably, a support material is used that has an averagepore diameter of from 50 to 500 Å, and most desirably from 75 to 350 Å.It may be particularly desirable to dehydrate the silica at atemperature of from 100° C. to 800° C. anywhere from 3 to 24 hours.

Suitably, the support may be flexible or a rigid support, the insolublesupport is coated and/or impregnated with the compounds of the processof the invention by techniques well known to those skilled in the art.

Alternatively, the compounds of the process of the invention are fixedto the surface of an insoluble support, optionally via a covalent bond,and the arrangement optionally includes a bifunctional spacer moleculeto space the compound from the insoluble support.

The compounds of the invention may be fixed to the surface of theinsoluble support by promoting reaction of a functional group present inthe compound of formula 1, for example a substituent of the aromaticstructure, with a complimentary reactive group present on or previouslyinserted into the support. The combination of the reactive group of thesupport with a complimentary substituent of the compound of theinvention provides a heterogeneous catalyst where the compound of theinvention and the support are linked via a linkage such as an ether,ester, amide, amine, urea, keto group.

The choice of reaction conditions to link a compound of the process ofthe present invention to the support depends upon the ethylenicallyunsaturated compound and the groups of the support. For example,reagents such as carbodiimides, 1,1′-carbonyldiimidazole, and processessuch as the use of mixed anhydrides, reductive amination may beemployed.

According to a further aspect, the present invention provides the use ofthe process or ligand catalyst composition of any aspect of theinvention wherein the catalyst is attached to a support.

Additionally, the bidentate phosphine may be bonded to a suitablepolymeric substrate via at least one of the bridge substituents, thebridging group R, the linking group A or the linking group B e.g. 1,2bis(di-t-butylphosphinomethyl)-4-t-butyl-benzene may be bonded,preferably, via the 3, 5 or 6 cyclic carbons of the benzene group topolystyrene to give an immobile heterogeneous catalyst.

The amount of bidentate ligand used can vary within wide limits.Preferably, the bidentate ligand is present in an amount such that theratio of the number of moles of the bidentate ligand present to thenumber of moles of the Group 8, or 10 metal present is from 1 to 50 e.g.1 to 15 and particularly from 1 to 10 mol per mol of metal. Morepreferably, the mol: mol range of compounds of formula 1to Group 8, 9 or10 metal is in the range of 1:1 to 20:1, most preferably in the range of1:1 to 10:1 or even 1:1 to 1.5:1. Conveniently, the possibility ofapplying these low molar ratios is advantageous, as it avoids the use ofan excess of the compound of formula 1and hence minimises theconsumption of these usually expensive compounds. Suitably, thecatalysts of the invention are prepared in a separate step precedingtheir use in-situ in the carbonylation reaction.

Conveniently, the process of the invention may be carried out bydissolving the Group 8, 9 or 10 metal or compound thereof as definedherein in a suitable solvent such as one of the alkanols or aproticsolvents previously described (a particularly preferred solvent would bethe ester or acid product of the specific carbonylation reaction e.g.2-acetoxymethylpropionate or 3-acetoxymethylpropionate for vinyl acetatecarbonylation or methyl propionate for ethylene carbonylation) andsubsequently admixing with a compound of formula 1as defined herein.

The carbon monoxide may be used in the presence of other gases which areinert in the reaction. Examples of such gases include hydrogen,nitrogen, carbon dioxide and the noble gases such as argon.

The product of the reaction may be separated from the other componentsby any suitable means. However, it is an advantage of the presentprocess that significantly fewer by-products are formed thereby reducingthe need for further purification after the initial separation of theproduct as may be evidenced by the generally significantly higherselectivity. A further advantage is that the other components whichcontain the catalyst system which may be recycled and/or reused infurther reactions with minimal supplementation of fresh catalyst.

Preferably, the carbonylation is carried out at temperatures of between−30 to 170° C., more preferably −10° C. to 160° C., most preferably 20°C. to 150° C. An especially preferred temperature is one chosen between40° C. to 150° C. Advantageously, the carbonylation can be carried outat moderate temperatures, it is particularly advantageous to be able tocarry out the reaction at room temperature (20° C.)

Preferably, when operating a low temperature carbonylation, thecarbonylation is carried out between −30° C. to 49° C., more preferably,−10° C. to 45° C., still more preferably 0° C. to 45° C., mostpreferably 10° C. to 45° C. Especially preferred is a range of 10 to 35°C.

Preferably, the carbonylation is carried out at a CO partial pressure ofbetween 0.80×10⁵ N.m⁻²-90×10⁵N.m⁻², more preferably 1×10⁵ N.m^(−2−65×10)⁵N.m⁻², most preferably 1−50×10⁵ N.m². Especially preferred is a COpartial pressure of 5 to 45×10⁵N.m⁻².

Preferably, a low pressure carbonylation is also envisaged. Preferably,when operating a low pressure carbonylation the carbonylation is carriedout at a CO partial pressure of between 0.1 to 5×10⁵N.m⁻², morepreferably 0.2 to 2×10⁵N.m⁻², most preferably 0.5 to 1.5×10⁵N.m⁻².

There is no particular restriction on the duration of the carbonylationexcept that carbonylation in a timescale which is commerciallyacceptable is obviously preferred. Carbonylation in a batch reaction maytake place in up to 48 hours, more typically, in up to 24 hours and mosttypically in up to 12 hours. Typically, carbonylation is for at least 5minutes, more typically, at least 30 minutes, most typically, at least 1hour. In a continuous reaction such time scales are obviously irrelevantand a continuous reaction can continue as long as the TON iscommercially acceptable before catalyst requires replenishment.

The catalyst system of the present invention is preferably constitutedin the liquid phase which may be formed by one or more of the reactantsor by the use of a suitable solvent.

The use of stabilising compounds with the catalyst system may also bebeneficial in improving recovery of metal which has been lost from thecatalyst system. When the catalyst system is utilized in a liquidreaction medium such stabilizing compounds may assist recovery of thegroup 8, 9 or 10 metal.

Preferably, therefore, the catalyst system includes in a liquid reactionmedium a polymeric dispersant dissolved in a liquid carrier, saidpolymeric dispersant being capable of stabilising a colloidal suspensionof particles of the group 8, 9 or 10 metal or metal compound of thecatalyst system within the liquid carrier.

The liquid reaction medium may be a solvent for the reaction or maycomprise one or more of the reactants or reaction products themselves.The reactants and reaction products in liquid form may be miscible withor dissolved in a solvent or liquid diluent.

The polymeric dispersant is soluble in the liquid reaction medium, butshould not significantly increase the viscosity of the reaction mediumin a way which would be detrimental to reaction kinetics or heattransfer. The solubility of the dispersant in the liquid medium underthe reaction conditions of temperature and pressure should not be sogreat as to deter significantly the adsorption of the dispersantmolecules onto the metal particles.

The polymeric dispersant is capable of stabilising a colloidalsuspension of particles of said group 8, 9 or 10 metal or metal compoundwithin the liquid reaction medium such that the metal particles formedas a result of catalyst degradation are held in suspension in the liquidreaction medium and are discharged from the reactor along with theliquid for reclamation and optionally for re-use in making furtherquantities of catalyst. The metal particles are normally of colloidaldimensions, e.g. in the range 5-100 nm average particle size althoughlarger particles may form in some cases. Portions of the polymericdispersant are adsorbed onto the surface of the metal particles whilstthe remainder of the dispersant molecules remain at least partiallysolvated by the liquid reaction medium and in this way the dispersedgroup 8, 9 or 10 metal particles are stabilised against settling on thewalls of the reactor or in reactor dead spaces and against formingagglomerates of metal particles which may grow by collision of particlesand eventually coagulate. Some agglomeration of particles may occur evenin the presence of a suitable dispersant but when the dispersant typeand concentration is optimised then such agglomeration should be at arelatively low level and the agglomerates may form only loosely so thatthey may be broken up and the particles redispersed by agitation.

The polymeric dispersant may include homopolymers or copolymersincluding polymers such as graft copolymers and star polymers.

Preferably, the polymeric dispersant has sufficiently acidic or basicfunctionality to substantially stabilise the colloidal suspension ofsaid group 8, 9 or 10 metal or metal compound.

By substantially stabilise is meant that the precipitation of the group8, 9 or 10 metal from the solution phase is substantially avoided.

Particularly preferred dispersants for this purpose include acidic orbasic polymers including carboxylic acids, sulphonic acids, amines andamides such as polyacrylates or heterocycle, particularly nitrogenheterocycle, substituted polyvinyl polymers such as polyvinylpyrrolidone or copolymers of the aforesaid.

Examples of such polymeric dispersants may be selected frompolyvinylpyrrolidone, polyacrylamide, polyacrylonitrile,polyethylenimine, polyglycine, polyacrylic acid, polymethacrylic acid,poly(3-hydroxybutyricacid), poly-L-leucine, poly-L-methionine,poly-L-proline, poly-L-serine, poly-L-tyrosine,poly(vinylbenzenesulphonic acid) and poly(vinylsulphonic acid), acylatedpolyethylenimine. Suitable acylated polyethylenimines are described inBASF patent publication EP1330309 A1 and U.S. Pat. No. 6,723,882.

Preferably, the polymeric dispersant incorporates acidic or basicmoieties either pendant or within the polymer backbone. Preferably, theacidic moieties have a dissociation constant (pK_(a)) of less than 6.0,more preferably, less than 5.0, most preferably less than 4.5.Preferably, the basic moieties have a base dissociation constant(pK_(b)) being of less than 6.0, more preferably less than 5.0 and mostpreferably less than 4.5, pK_(a) and pK_(b) being measured in diluteaqueous solution at 25° C.

Suitable polymeric dispersants, in addition to being soluble in thereaction medium at reaction conditions, contain at least one acidic orbasic moiety, either within the polymer backbone or as a pendant group.We have found that polymers incorporating acid and amide moieties suchas polyvinylpyrollidone (PVP) and polyacrylates such as polyacrylic acid(PAA) are particularly suitable. The molecular weight of the polymerwhich is suitable for use in the invention depends upon the nature ofthe reaction medium and the solubility of the polymer therein. We havefound that normally the average molecular weight is less than 100,000.Preferably, the average molecular weight is in the range 1,000-200,000,more preferably, 5,000-100,000, most preferably, 10,000-40,000 e.g. Mwis preferably in the range 10,000-80,000, more preferably 20,000-60,000when PVP is used and of the order of 1,000-10,000 in the case of PAA.

The effective concentration of the dispersant within the reaction mediumshould be determined for each reaction/catalyst system which is to beused.

The dispersed group 8, 9 or 10 metal may be recovered from the liquidstream removed from the reactor e.g. by filtration and then eitherdisposed of or processed for re-use as a catalyst or other applications.In a continuous process the liquid stream may be circulated through anexternal heat-exchanger and in such cases it may be convenient to locatefilters for the palladium particles in these circulation apparatus.

Preferably, the polymer:metal mass ratio in g/g is between 1:1 and1000:1, more preferably, between 1:1 and 400:1, most preferably, between1:1 and 200:1. Preferably, the polymer:metal mass ratio in g/g is up to1000, more preferably, up to 400, most preferably, up to 200.

It will be appreciated that any of the features set forth in the firstaspect of the invention may be regarded as preferred features of thesecond, third, fourth, fifth or other aspect of the present inventionand vice versa.

The invention not only extends to novel bidentate ligands of formula (I)but also novel complexes of such ligands with the metal of Group 8, 9 or10 or a compound thereof.

The invention will now be described and illustrated by way of thefollowing non-limiting examples and comparative examples.

SYNTHESIS EXAMPLES Preparation of Example Ligands of the Invention is asFollows Compound 1 Synthesis of1,2-bis(di-tert-butylphosphinomethyl)-4trimethylsilyl benzene Part (I)Synthesis of 4-trimethylsilyl-o-xylene

Magnesium ribbon (2.91 g, 115.41 mmol) was added to a schlenk flask. Tothis was added a few (3-4) crystals of iodine. THF (150 ml) was thenadded to give an orange/yellow solution. 4-bromo-o-xylene (19.41 g,104.91 mmol) was diluted with THF (80 ml) and then added slowly over onehour to the magnesium suspension, the reaction flask being placed in awarm (50° C.) water bath for the duration of the reaction. This gave adark orange/brown solution with some insoluble magnesium. This solutionwas then heated to 85° C. for one hour. The solution was then allowed tocool to room temperature before being cannula transferred into a cleanschlenk away for the unreacted magnesium. The THF solution was thencooled to −78° C. before trimethylsilyl chloride (13.41 ml, 104.91 mmol)was added by syringe. The resultant solution was then allowed to stir at−78° C. for thirty minutes before being allowed to warm to roomtemperature. The resultant solution was then stirred at room temperatureovernight. The solution was quenched by the addition of water (100 ml).Ether (100 ml) was then added and the biphasic mixture separated. Theaqueous layer was washed with ether (100 ml) and the organic extractscombined. The organic extracts were then dried over sodium sulphatebefore being filtered. The filtrate was then dried under vacuum to givea colourless oil. Yield=14.47 g, 77%.

Part (II)

The 4-trimethylsilyl-o-xylene (5.00 g, 28.1 mmol) (prepared in Part (I)was diluted with heptane (100 ml) and to this was added NaOBu^(t) (8.1g, 84.3 mmol), TMEDA (12.6 ml, 84.3 mmol) and Bu^(n)Li (2.5M in hexanes,33.7 ml, 84.3 mmol). The butyl lithium was added dropwise and gave animmediate colour change from colourless to yellow to orange to dark red.The solution was then heated to 65° C. for three hours. This gave abrown/orange suspension. The suspension was cooled to room temperatureand the supernatant liquid removed by cannula. The brown precipitateresidue was then washed with pentane (100 ml). The pentane washings werethen removed by cannula. The solid residue was then suspended in pentane(100 ml) and then cooled in a cold water bath. Bu^(t) ₂PCl (7.5 ml, 39.3mmol) was then added dropwise to the suspension. The resultantsuspension was then stirred for three hours and stood overnight. Water(100 ml) was degassed with nitrogen gas for 30 minutes and then added tothe suspension. This gave a biphasic solution. The upper (organic phase)was diluted with pentane (100 ml) and the organic phase removed bycannula into a clean schlenk flask. The pentane extract was then driedover sodium sulphate and transferred into a clean schlenk flask bycannula. The solvent was then removed under vacuum to give orange oil.To this was added methanol (100 ml) which give a biphasic solution. Thiswas then heated to reflux (70° C.) which gave a pale yellow solution andsome colourless insoluble material. The solution was then cooled to roomtemperature and filtered into a clean schlenk flask. The solution wasthen placed in the freezer at −20° C. overnight. This gave thedeposition of an off-white solid. The remaining methanol solution wasthen removed by cannula and the solid dried under vacuum. The solid wasisolated in the glovebox. Yield=4.70 g, 36%. 92% pure. ³¹P CHI NMR(CDCl₃, 161.9 MHz, 5); 27.3 (s), 26.1 (s) ppm.

Compound 2 Synthesis of1,2-bis(di-tert-butylphosphinomethyl)-4-tert-butyl-benzene

The 4-tert-butyl-o-xylene (4.55 g, 28.1 mmol) (Aldrich) was diluted withheptane (100 ml) and to this was added NaOBu^(t) (8.1 g, 84.3 mmol),TMEDA (12.6 ml, 84.3 mmol) and Bu^(n)Li (2.5M in hexanes, 33.7 ml, 84.3mmol). The butyl lithium was added dropwise and gave an immediate colourchange from colourless to yellow to orange to dark red. The solution wasthen heated to 65° C. for three hours. This gave a brown/orangesuspension. The suspension was cooled to room temperature and thesupernatant liquid removed by cannula the brown precipitate residue wasthen washed with pentane (100 ml. The pentane washings were then removedby cannula. The solid residue was then suspended in pentane (100 ml) andthen cooled in a cold water bath. Bu^(t) ₂PCl (7.5 ml, 39.3 mmol) wasthen added dropwise to the suspension. The resultant suspension was thenstirred for three hours and stood overnight. Water (100 ml) was degassedwith nitrogen gas for 30 minutes and then added to the suspension. Thisgave a biphasic solution. The upper (organic phase) was diluted withpentane (100 ml) and the organic phase removed by cannula into a cleanschlenk flask. The pentane extract was then dried over sodium sulphateand transferred into a clean schlenk flask by cannula. The solvent wasthen removed under vacuum to give orange oil. To this was added methanol(100 ml) which give a biphasic solution. This was then heated to reflux(70° C.) which gave a pale yellow solution and some colourless insolublematerial. The solution was then cooled to room temperature and filteredinto a clean schlenk flask. The solution was then placed in the freezerat −20° C. overnight. This gave the deposition of an off-white solid.The remaining methanol solution was then removed by cannula and thesolid dried under vacuum. The solid was isolated in the glovebox.Yield=4.20 g, 33%. 95% pure. ³¹P CHI NMR (CDCl₃, 161.9 MHz, 5); 27.1(s), 26.3 (s) ppm.

Compound 3 Synthesis of1,2-bis(di-tert-butylphosphinomethyl)-1′-(triphenylsilyl) ferrocene Part(I) Preparation of 1-bromo-1′-triphenylsilyl ferrocene

To 1,1′-dibromoferrocene (10.14 g, 29.49 mmol) in dry THF (200 ml)cooled to −78° C. (dry ice/acetone bath) was added n-butyllithium (12.56ml, 28.02 mmol, 0.95 eq) and the reaction was stirred under N₂ for 30min. Chlorotriphenylsilane (8.26 g, 28.02 mmol, 0.95 eq) dissolved inthe minimum amount of dry THF was then added dropwise and the solutionwas then allowed to warm up to room temperature and further stirred fortwelve hours resulting in a red solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite. The ether solvent was removed by rotaryevaporator (resulting in red oil). The product was purified by columnchromatography. Starting material was removed with petrol and theproduct was then obtained with petrol/10% Et₂O as an orange band. Theresulting oil was finally dried under vacuum leaving pure product asorange crystals: (11.09 g, 72% yield).

Part (II) Preparation of 1-dimethylaminomethyl-1′-triphenylsilylferrocene

To 1-bromo-1′-triphenylsilyl ferrocene (8 g, 15.29 mmol) in dry diethylether (100 ml) was added n-butyllithium (6.73 ml, 16.82 mmol, 1.1 eq)and the reaction was stirred under N₂ for 1 hour at room temperature.Dry THF (100 ml) was then added and solution was then cooled to −78° C.(dry ice/acetone bath) and quenched with Eschenmoser's salt (3.11 g,16.82 mmol, 1.1 eq). The solution was then allowed to warm up to roomtemperature and further stirred for twelve hours resulting in a yellowsolution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite. The ether solvent was removed by rotaryevaporator (resulting in red oil). The product was purified by columnchromatography. Starting material was removed with petrol (10% Et₂O) andthe product was then obtained with 1:1 petrol/Et₂O (5% triethylamine).The resulting red oil was finally dried under vacuum leaving pureproduct as red/orange crystals: (3 g, 39% yield).

Part (III) Preparation of 1,2-bis-dimethylaminomethyl-1′-triphenylsilylferrocene

To 1-dimethylaminomethyl-1′-triphenylsilyl ferrocene (2.66 g, 5.30 mmol)in dry diethyl ether (100 ml) was added n-butyllithium (2.55 ml, 6.36mmol, 1.2 eq) and the reaction was stirred under N₂ for 1 hour at roomtemperature. Dry THF (100 ml) was then added and solution was thencooled to −78° C. (dry ice/acetone bath) and quenched with Eschenmoser'ssalt (1.08 g, 5.83 mmol, 1.1 eq). The solution was then allowed to warmup to room temperature and further stirred for twelve hours resulting inan orange solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite. The ether solvent was removed by rotaryevaporator (resulting in red oil). The product was purified by columnchromatography. Starting material was removed with petrol (10% Et₂O) andthe product was then obtained with 1:1 petrol/Et₂O (5% triethylamine).The resulting red oil was finally dried under vacuum: (2.94 g, 99%yield).

Part (IV) 1,2-bis(dimethylaminomethyl)-1′-(triphenylsilyl)ferrocene

(5.15 g, 9.23 mmol) and di-tert-butylphosphine (4.00 g, 27.40 mmol) wereadded together in a schlenk flask. To this was added acetic acid:aceticanhydride (100 ml: 10 ml) which had been degassed with nitrogen for 30minutes. The resultant suspension was then heated to 130° C. for fivehours. The solution was then cooled to room temperature and the solventremoved under vacuum. The residue was suspended in methanol (50 ml) andstirred for 20 minutes. The methanol was then removed under vacuum. Theresidue was then suspended in ethanol (50 ml) and the ethanol suspensionheated to reflux. This gave a red solution which was then allowed tocool to room temperature before being placed in the freezer overnight at−20° C. This gave the precipitation of an red-orange solid. The motherliquor was cannula transferred into a clean schlenk and the residuedried under vacuum. This solid was then isolated in the glovebox.Yield=2.8 g, 40%. 95% pure. ³¹P CHI NMR (CDCl₃, 161.9 MHz, 5); 23.5 ppm

Compound 4 Synthesis of1,2-bis(di-tert-butylphosphinomethyl)-1′-3-bis(triphenylsilyl)ferrocenePart (I) Preparation of 1-dimethylaminomethyl-2,1′-bis-triphenylsilylferrocene

To dimethylaminomethylferrocene (20 g, 82.26 mmol) in dry diethyl ether(300 ml) was added n-butyllithium (82.26 ml, 205.65 mmol, 2.5 eq) andTMEDA (13.66 ml, 90.49 mmol, 1.1 eq) and the reaction was stirred underN₂ for 12 hours at room temperature. The solution was then cooled to−78° C. (dry ice/acetone bath) and quenched with chlorotriphenylsilane(50.94 g, 172.75 mmol, 2.1 eq) dissolved in dry THF (200 ml). Thesolution was then allowed to warm up to room temperature and furtherstirred for twelve hours resulting in a red solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite. The ether solvent was removed by rotaryevaporator (resulting in red oil). The product was purified by layeringthe oil with petrol and Et₂O and leaving to crystallize overnight. Theliquid residue was decanted and the orange/red crystals were dried undervacuum. A second crop of orange/red crystals were obtained with thelayering of the decanted liquid and repeating the process: (42.75 g, 68%yield).

Part (II) Preparation of1,2-bis-dimethylaminomethyl-3,1′-bis-triphenylsilyl ferrocene

To 1-dimethylaminomethyl-2,1′-bis-triphenylsilyl ferrocene (40 g, 52.63mmol) in dry diethyl ether (400 ml) was added n-butyllithium (25.26 ml,63.16 mmol, 1.2 eq) and the reaction was stirred under N₂ for 20 hoursat room temperature. Dry THF (250 ml) was then added and solution wasthen cooled to −78° C. (dry ice/acetone bath) and quenched withEschenmoser's salt (12.65 g, 68.42 mmol, 1.3 eq). The solution was thenallowed to warm up to room temperature and further stirred for twelvehours resulting in an orange solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite.

The ether solvent was removed by rotary evaporator (resulting in redoil). The product was purified by layering the oil with the minimum Et₂Oand a layer of petrol and leaving to crystallize overnight. The liquidresidue was decanted and the red crystals were dried under vacuum. Asecond crop of red crystals were obtained with the layering of thedecanted liquid and repeating the process: (21.50 g, 50% yield).

Part (III)

The 1,2-bis(dimethylaminomethyl)-1′-3-bis(triphenylsilyl)ferrocene(15.37 g, 18.84 mmol) and di-tert-butylphosphine (8.00 g, 54.79 mmol)were added together in a schlenk flask. To this was added aceticacid:acetic anhydride (100 ml: 10 ml) which had been degassed withnitrogen for 30 minutes. The resultant suspension was then heated to130° C. for four hours. The solution was then cooled to room temperatureand the solvent removed under vacuum. The residue was suspended inmethanol (100 ml) and stirred for 20 minutes. The methanol was thenremoved under vacuum. The residue was then suspended in ethanol (50 ml)and the ethanol suspension heated to 80° C. The resultant suspension wasthen allowed to cool to room temperature and the ethanol solublematerial filtered into a clean schlenk. The residue was dried undervacuum to give a pale orange solid. Yield=8.0 g, 42%. 95% pure. ³¹P CHINMR (CDCl₃, 161.9 MHz, 5); 23.9 (s), 20.4 (s) ppm

Compound 5 Synthesis of1,2-bis(di-tert-butylphosphinomethyl)-3-(triphenylsilyl)ferrocene Part(I) Preparation of 1-dimethylaminomethyl-2-triphenylsilyl ferrocene

To dimethylaminomethylferrocene (20 g, 82.26 mmol) in dry diethyl ether(300 ml) was added n-butyllithium (41.13 ml, 102.82 mmol, 1.25 eq) andTMEDA (13.66 ml, 90.49 mmol, 1.1 eq) and the reaction was stirred underN₂ for 12 hours at room temperature. The solution was then cooled to−78° C. (dry ice/acetone bath) and quenched with chlorotriphenylsilane(25.48 g, 86.38 mmol, 1.05 eq) dissolved in dry THF (200 ml). Thesolution was then allowed to warm up to room temperature and furtherstirred for twelve hours resulting in a red solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite. The ether solvent was removed by rotaryevaporator (resulting in red oil). The product was purified by layeringthe oil with petrol and Et₂O and leaving to crystallize overnight. Theliquid residue was decanted and the orange/red crystals were dried undervacuum. A second crop of orange/red crystals were obtained with thelayering of the decanted liquid and repeating the process: (25.63 g, 62%yield).

Part (II) Preparation of1,2-bis-dimethylaminomethyl-3,1′-bis-triphenylsilyl ferrocene

To 1-dimethylaminomethyl-2-triphenylsilyl ferrocene (20 g, 39.87 mmol)in dry diethyl ether (400 ml) was added n-butyllithium (19.13 ml, 47.84mmol, 1.2 eq) and the reaction was stirred under N₂ for 20 hours at roomtemperature. Dry THF (250 ml) was then added and solution was thencooled to −78° C. (dry ice/acetone bath) and quenched with Eschenmoser'ssalt (9.59 g, 51.83 mmol, 1.3 eq). The solution was then allowed to warmup to room temperature and further stirred for twelve hours resulting inan orange solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite. The ether solvent was removed by rotaryevaporator (resulting in red oil). The product was purified by layeringthe oil with the minimum Et₂O and a layer of petrol and leaving tocrystallize overnight. The liquid residue was decanted and the redcrystals were dried under vacuum. A second crop of red crystals wereobtained with the layering of the decanted liquid and repeating theprocess: (14.7 g, 66% yield).

Part (III)

The diamine from Part (II) (5.00 g, 8.96 mmol) anddi-tert-butylphosphine (3.50 g, 23.97 mmol) were added together in aschlenk flask. To this was added acetic acid:acetic anhydride (100 ml:10 ml) which had been degassed with nitrogen for 30 minutes. Theresultant suspension was then heated to 130° C. for three hours. Thesolution was then cooled to room temperature and the solvent removedunder vacuum. The residue was suspended in methanol (50 ml) and stirredfor 20 minutes. The methanol was then removed under vacuum. Pentane (50ml) was then added and the pentane soluble material cannula transferredinto a clean schlenk. The solvent was the removed under vacuum to givean orange/red oily solid. Yield=2.0 g, 30%. 90% pure. ³¹P CHI NMR(CDCl₃, 161.9 MHz, 5); 26.0 (s), 20.3 (s) ppm

Compound 6 Preparation of1,2-bis(di-1-(3,5-dimethyladamantyl)phosphinomethyl)-1′-trimethylsilyl-ferrocenePart (I) Preparation of 1-bromo-1′-trimethylsilyl ferrocene

To 1,1′-dibromoferrocene (10 g, 29.08 mmol) in dry THF (200 ml) cooledto −78° C. (dry ice/acetone bath) was added n-butyllithium (11.05 ml,27.63 mmol, 0.95 eq) and the reaction was stirred under N₂ for 30 min.Chlorotrimethylsilane (3.7 ml, 29.08 mmol, 1 eq) was then added dropwiseand the solution was then allowed to warm up to room temperature andfurther stirred for twelve hours resulting in a red solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite. The ether solvent was removed by rotaryevaporator (resulting in red oil). The product was purified as theinitial red band (petrol) by column chromatography. The resulting redoil was finally dried under vacuum: (7.11 g, 73% yield).

Part (II) Preparation of 1-dimethylaminomethyl-1′-trimethylsilylferrocene

To 1-bromo-1′-trimethylsilyl ferrocene (5.52 g, 16.37 mmol) in drydiethyl ether (100 ml) was added n-butyllithium (7.2 ml, 18.01 mmol, 1.1eq) and the reaction was stirred under N₂ for 1 hour at roomtemperature. Dry THF (100 ml) was then added and solution was thencooled to −78° C. (dry ice/acetone bath) and quenched with Eschenmoser'ssalt (3.33 g, 18 mmol, 1 eq). The solution was then allowed to warm upto room temperature and further stirred for twelve hours resulting in ayellow solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite. The ether solvent was removed by rotaryevaporator (resulting in red oil). The product was purified by columnchromatography. Starting material was removed with petrol (10% Et₂O) andthe product was then obtained with 1:1 petrol/Et₂O (5% triethylamine).The resulting red oil was finally dried under vacuum: (4.09 g, 79%yield).

Part (III) Preparation of 1,2-bis-dimethylaminomethyl-1′-trimethylsilylferrocene

To 1-dimethylaminomethyl-1′-trimethylsilyl ferrocene (3.86 g, 12.24mmol) in dry diethyl ether (100 ml) was added n-butyllithium (5.88 ml,14.69 mmol, 1.2 eq) and the reaction was stirred under N₂ for 1 hour atroom temperature. Dry THF (100 ml) was then added and solution was thencooled to −78° C. (dry ice/acetone bath) and quenched with Eschenmoser'ssalt (2.50 g, 13.47 mmol, 1.1 eq). The solution was then allowed to warmup to room temperature and further stirred for twelve hours resulting inan orange solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite.

The ether solvent was removed by rotary evaporator (resulting in redoil). The product was purified by column chromatography. Startingmaterial was removed with petrol (10% Et₂O) and the product was thenobtained with 1:1 petrol/Et₂O (5% triethylamine). The resulting red oilwas finally dried under vacuum: (4.33 g, 95% yield).

Part (IV) Synthesis of1,2-bis(di-1(3,5-dimethyladamantyl)phosphinomethyl)-1′(trimethylsilyl)ferrocene

The diamine Part (III) (1.00 g, 2.68 mmol) was dissolved in acetic acid:acetic anhydride (18 ml: 2 ml) which had been degassed with nitrogen for10 minutes. The diamine solution was then transferred by cannula into a500 ml schlenk flask containing the dimethyl adamantyl phosphine (1.98g, 5.36 mmol). The resultant suspension was then heated to 130° C. forfive hours. The solution was then cooled to room temperature and thesolvent removed under vacuum. The residue was suspended in methanol (50ml) and stirred for 20 minutes. The methanol was then removed undervacuum. The residue was then washed with ethanol (50 ml) and the ethanolwashings removed by cannula. The remaining solid was then dried undervacuum and isolated in the glovebox as a yellow/orange solid. Yield=1.10g, 41%. 86% pure. ³¹P CHI NMR (CDCl₃, 161.9 MHz, 5); 18.7 ppm.

Compound 7 Preparation of 1,2-bis(di-tert-butyl(phosphinomethyl) 3,5,1′tris-triphenylsilyl ferrocene Part (I) Preparation of1,2-bis-dimethylaminomethyl-3,5,1′tris-triphenylsilyl ferrocene

To 1,2-bis-dimethylaminomethyl-3,1′-bis-triphenylsilyl ferrocene (10.2g, 12.48 mmol) (prepared as in compound 4 above) in dry diethyl ether(200 ml) was added n-butyllithium (5.99 ml, 14.98 mmol, 1.2 eq) and thereaction was stirred under N₂ for 4 hours at room temperature. Thesolution was then cooled to −78° C. (dry ice/acetone bath) and quencheddropwise with chlorotriphenylsilane (4.78 g, 16.23 mmol, 1.3 eq)dissolved in the minimum amount of dry diethyl ether. The solution wasthen allowed to warm up to room temperature and further stirred fortwelve hours resulting in a red solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite. The ether solvent was removed by rotaryevaporator (resulting in red oil). The product was purified by layeringthe oil with the minimum Et₂O and a layer of petrol and leaving tocrystallize overnight. The liquid residue was decanted and the redcrystals obtained were dried under vacuum: (10.41 g, 78% yield).

The produced 1,2-bis-dimethylaminomethyl-3,5,1′-tris-triphenylsilylferrocene (18.24 mmol) was made into the di-tert-butylphosphine asfollows.

Part (II) Synthesis of1,2-bis(di-tert-butylphosphinomethyl)-1′-3-5-tris(triphenylsilyl)ferrocene

The diamine from Part (I) (10.41 g, 9.69 mmol) anddi-tert-butylphosphine (5.00 g, 34.2 mmol) were added together in aschlenk flask. To this was added acetic acid:acetic anhydride (100 ml:10 ml) which had been degassed with nitrogen for 30 minutes. Theresultant suspension was then heated to 130° C. for four hours. Thesolution was then cooled to room temperature and the solvent removedunder vacuum. The residue was suspended in methanol (100 ml) and stirredfor 20 minutes. The methanol was then removed under vacuum. Pentane (50ml) was then added and the pentane soluble material cannula transferredinto a clean schlenk. The solvent was the removed under vacuum to give apale orange/brown solid. Yield=1.7 g, 14%. 95% pure. ³¹P {¹H} NMR(CDCl₃, 161.9 MHz, 5); 23.9 (s), 20.4 (s) ppm

Compound 8 Preparation of1,2-bis(di-tert-butylphosphinomethyl)-3,1′-bis-trimethylsilyl ferrocenePart (I) Preparation of 1-dimethylaminomethyl-2,1′-bis-trimethylsilylferrocene

To dimethylaminomethylferrocene (30 g, 123.39 mmol) (Aldrich) in drydiethyl ether (200 ml) was added n-butyllithium (123.39 ml, 308.48 mmol,2.5 eq) and TMEDA (20.48 ml, 135.73 mmol, 1.1 eq) and the reaction wasstirred under N₂ for 12 hours at room temperature. The solution was thencooled to −78° C. (dry ice/acetone bath) and quenched withchlorotrimethylsilane (34.45 ml, 271.46 mmol, 2.2 eq). The solution wasthen allowed to warm up to room temperature and further stirred fortwelve hours resulting in an orange solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite. The ether solvent was removed by rotaryevaporator (resulting in red oil). The product was purified by columnchromatography (large scale column). Small amounts of starting materialwere removed with petrol (5% triethylamine) and the product was thenobtained with 1:1 petrol/Et₂O (5% triethylamine). The resulting red oilwas finally dried under vacuum: (40 g, 84% yield).

Part (II) Preparation of1,2-bis-dimethylaminomethyl-3,1′-bis-trimethylsilyl ferrocene

To 1-dimethylaminomethyl-2,1′-bis-trimethylsilyl ferrocene (30 g, 77.42mmol) in dry diethyl ether (200 ml) was added n-butyllithium (37.2 ml,92.91 mmol, 1.2 eq) and the reaction was stirred under N₂ for 20 hoursat room temperature. Dry THF (250 ml) was then added and solution wasthen cooled to −78° C. (dry ice/acetone bath) and quenched withEschenmoser's salt (17.18 g, 92.91 mmol, 1.2 eq). The solution was thenallowed to warm up to room temperature and further stirred for twelvehours resulting in a red solution.

The reaction was then quenched with water, and stirred for a furtherfifteen minutes. The ethereal layer, containing product was separatedand the aqueous layer was further extracted several times with diethylether. The combined ether fractions were dried over magnesium sulphateand filtered through celite. The ether solvent was removed by rotaryevaporator (resulting in red oil). The product was purified by columnchromatography (large scale column). Small amounts of starting materialwere removed with petrol (5% triethylamine) and the product was thenobtained with 1:1 petrol/Et₂O (5% triethylamine). The resulting red oilwas finally dried under vacuum: (32.11 g, 93% yield).

Part (III) Compound 8 was prepared as compound 3 above using1,2-bis-dimethylaminomethyl-3,1′-bis-trimethylsilyl ferrocene (9.23mmol) instead of1,2-bis(dimethylaminomethyl)-1′-(triphenylsilyl)ferrocene.

Compound A

Synthesis of 1,2-bis(di-tert-butylphosphinomethyl)-4-CMe₂Ph-benzene Part(I) Synthesis of 4-CMe₂Ph-o-xylene

The 3,4-dimethylbenzophenone (15.0 g, 71.43 mmol) was added to a 500 mlschlenk flask, to this was added benzoic acid (150 mg). The solid wasthen dissolved in toluene (100 ml). To this was then added trimethylaluminium (2.0M in toluene, 100 ml, 200 mmol). The resultant solutionwas then heated to 125° C. for hours. The solution was then allowed tocool to room temperature and was then quenched by the very slow additionof water (100 ml). This gave a white suspension, diethyl ether (150 ml)was then added and the suspension filtered. The filtrate was then driedover sodium sulphate and filtered. The filtrate was then dried undervacuum, this gave a colourless oil, yield=13.4 g, 84%.

The 4-CMe₂Ph-o-xylene ((13.0 g, 58.0 mmol) from Part I above andNaOBu^(t) (16.7 g, 174.1 mmol) were added together in a schlenk flask.To this was then added heptane (150 ml) and TMEDA (26.1 ml, 174.1 mmol),Bu^(n)Li (2.5M in hexanes, 69.6 ml, 174.1 mmol) was then added slowly.The addition of the butyl lithium gave an immediate colour change fromcolourless to yellow to orange to dark red. The resultant solution wasthen heated to 70° C. for three hours. This gave a dark red suspension.The suspension was cooled to room temperature and the supernatant liquidremoved by cannula the brown precipitate residue was then washed withpentane (200 ml). The pentane washings were then removed by cannula. Thesolid residue was then suspended in pentane (250 ml) and then cooled to0° C. Bu^(t) ₂PCl (19.8 ml, 104.5 mmol) was then added dropwise to thesuspension. The resultant suspension was then stirred for overnight.Water (100 ml) was degassed with nitrogen gas for 30 minutes and thenadded to the suspension. This gave a biphasic solution. The upper(organic phase) was diluted with pentane (100 ml) and the organic phaseremoved by cannula into a clean schlenk flask. The aqueous layer wasthen washed with a further 100 ml of pentane and the pentane extractscombined. The pentane extracts were then dried over sodium sulphate andtransferred into a clean schlenk flask by cannula. The solvent was thenremoved under vacuum to give a red/brown oil. Methanol (100 ml) was thenadded and the resultant suspension heated to reflux, the suspensionformed was then allowed to cool to room temperature and the methanolsoluble material removed by cannula. The residue was dried under vacuumto give an orange/brown oil. Yield=10.9 g, 45%. ³¹P CHI NMR wasconsistent with the structure, the compound was cleaned up by conversionto the bis methane sulphonate salt—see below.

Synthesis of bis methane sulphonic acid salt of1,2-bis(di-tert-butylphosphinomethyl)-4-CMe₂Ph-benzene

The phosphine (Compound A) (10.9 g, 21.3 mmol) was suspended in methanol(100 ml). To this was added methane sulphonic acid (2.76 ml, 42.6 mmol).The resultant solution was then stirred for one hour. The methanol wasthen removed under vacuum to give viscous brown oil. Diethyl ether (50ml) was then added, and the ether soluble material was removed bycannula. The remaining material was then dried under vacuum this gave asticky yellow solid. Diethyl ether (60 ml) was then added and the solidwas stirred in the ether with a spatula. The ether soluble material wasthen removed and the residue dried under vacuum, this gave a freeflowing pale yellow solid. Yield=11.0 g, 85%. 95% pure. ³¹P {¹H} NMR(CDCl₃, 161.9 MHz, δ); 42.6 (br), 39.0 (br) ppm.

Compound B

Synthesis of1,2-bis(di-tert-butylphosphinomethyl)-4-tert-butyldimethylsilyl benzenePart (I) Synthesis of 4-tert-butyldimethylsilyl-o-xylene

Magnesium ribbon (2.91 g, 115.41 mmol) was added to a schlenk flask. Tothis was added a few (3-4) crystals of iodine. THF (150 ml) was thenadded to give an orange/yellow solution. 4-bromo-o-xylene (19.41 g,104.91 mmol) was diluted with THF (80 ml) and then added slowly over onehour to the magnesium suspension, the reaction flask being placed in awarm (50° C.) water bath for the duration of the reaction. This gave adark orange/brown solution with some insoluble magnesium. This solutionwas then heated to 85° C. for one hour. The solution was then allowed tocool to room temperature before being cannula transferred into a cleanschlenk away for the unreacted magnesium. The THF solution was thencooled to −78° C. before a solution of tert-butyldimethylsilyl chloride(15.81 g, 104.91 mmol) in THF (50 ml) was added. The resultant solutionwas then allowed to stir at −78° C. for thirty minutes before beingallowed to warm to room temperature. The resultant solution was thenstirred at room temperature overnight. The solution was quenched by theaddition of water (100 ml). Ether (100 ml) was then added and thebiphasic mixture separated. The aqueous layer was washed with ether (100ml) and the organic extracts combined. The organic extracts were thendried over sodium sulphate before being filtered. The filtrate was thendried under vacuum to give a white solid. Yield=15.64 g, 68%.

Part (II)

The 4-tert-butyldimethylsilyl-o-xylene (7.5 g, 34.1 mmol) from Part (I)above and NaOBu^(t) (13.1 g, 136.4 mmol) were added together in aschlenk flask. Heptane (100 ml) was then added follwed by TMEDA (20.5ml, 136.4 mmol), Bu^(n)Li (2.5M in hexanes, 54.5 ml, 136.4 mmol) wasthen added slowly. The butyl lithium addition gave an immediate colourchange from colourless to yellow to orange to dark red. The solution wasthen heated to 75° C. for three hours. This gave a brown solution with asmall amount of precipitate. The solution was then cooled to 0° C. andBu^(t) ₂PCl (11 .ml, 62.5 mmol) was then added dropwise to thesuspension. The resultant suspension was then stirred overnight. Water(100 ml) was degassed with nitrogen gas for 30 minutes and then added tothe suspension. This gave a biphasic solution. The upper (organic phase)was diluted with pentane (150 ml) and the organic phase removed bycannula into a clean schlenk flask. Pentane (150 ml) was added to theaqueous residues and the pentane extracts combined. The pentane extractswere then dried over sodium sulphate and transferred into a cleanschlenk flask by cannula. The solvent was then removed under vacuum togive a brown oil. To this was added methanol (50 ml) which give abiphasic solution. This was then heated to reflux (70° C.) before beingallowed to cool to room temperature. The methanol soluble material wasthen cannula transferred into a clean schlenk flask and then placed inthe freezer at −20° C. overnight. This gave the formation of a brownoil. The methanol mother liquor was then transferred into a cleanschlenk flask and placed in the freezer. Upon standing in the freezerfor three days a pale brown solid had formed. The methanol mother liquorwas removed and the residue dried under vacuum. This gave a pale brownsolid. Yield=0.80 g, 5%. 95% pure. ³¹P CHI NMR (CDCl₃, 161.9 MHz, 5);28.3 (s), 26.0 (s) ppm.

The comparative examples were obtained as follows: —

Comparative 1 1,2-bis(di-tert-butylphosphinomethyl)benzene is availablefrom Aldrich. Comparative 2 Synthesis of1,2-bis(di-tert-butylphosphinomethyl)ferrocene Part (I) Preparation of1,2-bis-(dimethylaminomethyl)ferrocene

n-Butyllithium (Aldrich, 2.5 molar in hexane, 24 ml, 54 mmol) is addedto a solution of (dimethylaminomethyl)ferrocene (Aldrich, 13.13 g, 10.69ml, 48.97 mmol) in diethyl ether (80 ml) under nitrogen at a temperatureof 25° C. and the reaction mixture stirred for 4 hours. The resultingred solution is then cooled to approximately −70° C. in a dryice/acetone bath and Eschenmosers salt (ICH₂NMe₂) (Aldrich, 10 g, 54mmol) is added. The reaction is allowed to warm to room temperature andstirred overnight.

The resultant solution is quenched with excess aqueous sodium hydroxideand the resulting product extracted with diethyl ether (3×80 ml) driedover anhydrous magnesium sulfate, filtered over celite, and volatilesremoved in vacuo to yield the crude title compound as a light orangecrystalline solid. The crude product is recrystallised from light petrolwith cooling to −17° C. and the recrystallised product washed with coldpetrol to yield the title compound as a light orange solid (13.2 g,74%). The compound can be further purified by sublimation to give 8.5 g(52%) of the Part (I) title compound (mpt 74° C.)

¹H NMR (250 MHz; CDCl₃): δ4.23 (brd, 2H); 4.11-4.10 (t, 1H); 4.04 (s,5H); 3.43, 3.38, 3.23, 3.18 (AB quartet, 2H); 2.22 (s, 6H).

¹³C NMR (63 MHz; CDCl₃): δ83.81; 70.40; 69.25; 66.84; 57.35;

45.23.

Elemental analysis: Found: C 63.7%; H 8.9%; N 9.5%

-   -   Calculated: C 64.0%; H 8.1%; N 9.4%

Part (II)

Into a 500 ml schlenk flask was added the di-tert-butyl phosphine (13.3g, 90.8 mmol) and the 1,2-bis(dimethylaminomethyl)ferrocene (13.6 g,45.4 mmol). This was then suspended in a mixture of acetic acid:aceticanhydride 100 ml: 30 ml) which had been degassed with nitrogen for 30minutes. The suspension was then heated to 130° C. and kept at thistemperature for two hours. The resultant solution was then allowed tocool to ambient temperature and the solvent removed under vacuum. Theresultant sticky solid was suspended in methanol (50 ml) and stirred for30 minutes. The methanol was then removed under vacuum and the residuesuspended in ethanol (50 ml). The ethanol suspension was then heated upto 70° C. The resultant solution stirred was allowed to cool to roomtemperature before being placed in the freezer at −20° C. overnight.This gave a large amount of an orange crystalline product. The ethanolmother liquor was removed by cannula and the solid dried under vacuum.This gave free following orange crystals. Yield 15.1 g, 57%. ³¹P NMR{¹H}(CDCl₃, 161.9 MHz, 5); 23.6 ppm, 99% pure.

Comparative 3

Synthesis of1,2-bis(di-1-(3,5-dimethyladamantyl)phosphinomethyl)ferrocene Part (I)Preparation of 1-hydroxymethyl-2-dimethylaminomethyl ferrocene

n-Butyl lithium (Aldrich, 1.6 molar in diethyl ether, 5.14 ml, 8.24mmol) is added to a solution of 1-dimethylaminomethyl ferrocene(Aldrich, 1.0 g, 4.12 mmol) in diethyl ether (20 mL) under argon. Thereaction is stirred for 3 hours and develops a reddish colour. Thesolution is then cooled in a dry ice/acetone bath, calcinedpara-formaldehyde (0.247 g, 2 times excess) added and the resultantmixture stirred overnight at room temperature. The reaction is thenquenched with water, extracted with diethyl ether, dried over MgSO₄, andfiltered over celite. The solvent is removed in vacuo to yield crudetitle compound. The crude product is applied to a neutral aluminacolumn, which is eluted with petrol/diethyl ether (9:1 ratio) to removethe starting material, 1-dimethylaminomethyl ferrocene. The column isthen eluted with substantially pure ethyl acetate to elute the titlecompound. The ethyl acetate is removed in vacuo, to yield the titlecompound as an orange oil/crystalline mass.

¹H NMR (250 MHz; CDCl₃) δ2.131 (s, 6H), δ2.735 (d, 1H, 12.512 Hz),δ3.853 (d, 1H, 12.512 Hz), δ3.984 (dd, 1H, 2.156 Hz), δ4.035 (s, 5H),δ4.060 (dd, 1H, 2.136 Hz) δ4.071 (d, 1H, 12.207 Hz), δ4.154 (m, 1H),δ4.73 (d, 1H, 12.207 Hz).

¹³C NMR (61 MHz; CDCl₃) δ7.688, δ84.519, δ70.615, δ68.871, δ68.447,δ65.369, δ60.077, δ58.318, δ44.414

COSY 2D ¹H NMR

Partly obscured doublet at 4.071 ppm and its coupling to the doublet at4.73 ppm confirmed.

Infrared spectra (CHCl₃) (c.a. 0.06 g/0.8 mL) 2953.8 cm⁻¹, 2860.6 cm⁻¹,2826.0 cm⁻¹, 2783.4 cm⁻¹, 1104.9 cm⁻¹

Part (II)

Into a 500 ml schlenk flask was added the dimethyladamantyl phosphine(29.5 g, 82.3 mmol) and the 1-hydroxymethyl-2-dimethylaminomethylferrocene (11.2 g, 41.2 mmol) in the glovebox. This was then suspendedin a mixture of acetic acid:acetic anhydride (150 ml: 30 ml) which hadbeen degassed with nitrogen for 30 minutes. The suspension was thenheated to 130° C. and kept at this temperature for 60 minutes. Theresultant solution was then allowed to cool to ambient temperature andthe solvent removed under vacuum. The resultant sticky solid wassuspended in methanol (50 ml) and stirred for 30 minutes. The methanolwas then removed under vacuum and the residue suspended with ethanol(100 ml). The ethanol suspension was then stirred until a yellow/orangepowder was formed and a dark red/brown solution. The ethanol solublematerial washings were then removed by filtration and the residue driedunder vacuum. This gave a free flowing yellow/orange solid which wasisolated in the glovebox. Yield 26.7 g, 70.1%. ³¹P NMRCHI (CDCl₃, 161.9MHz, δ);18.9 ppm, 95% pure.

Test Results

Table 1 shows the activity of six phosphine ligands in catalysis afterthey have first been heated at 80° C. overnight in the presence ofCO/Ethene. In each case the number of moles of palladium, ligand andacid are the same as a standard batch run where the ligands have notbeen pre-treated (Table 2). Hence the gas uptake and weight gain of atreated (premature aged) ligand can be compared to a standard for theuntreated ligand. Thermal treatment is used to investigate differencesin catalyst stability which would not be evident in a standard 3 hourbatch test. In other words, conditions are employed which would resultin premature ageing of the catalyst.

It can be seen that the phosphine containing a trimethylsilyl group atthe 4 position of the benzene ring retains most of its activity underthese ageing conditions whereas the unsubstituted ligand1,2-bis(di-tert-butylphosphinomethyl) benzene has lost 85% of itsactivity of an untreated standard. In all the cases where a substituenton the ring is present an improvement over1,2-bis(di-tert-butylphosphinomethyl)benzene is observed.

TABLE 1 Results for New Ligands and 1,2-Bis (di-tert-butylphosphinomethyl)benzene for comparison Average % ActivityAverage Max of Gas Uptake TON MeP of Standard from 2.251 recycle (basedon Reservoir (mol Pd/mol GAS UPTAKE Ligand (bar) MeP) TON)

20.6 88182 100.34

12.5 52480 56.00

4.4 12095 13.01

20.3 82359 78.3

21.5 86493 98.86

21.3 86239 98.3

TABLE 2 Standards used for all aged ligands Average Max Gas Uptake TONMeP of from 2.251 recycle Reservoir (mol Pd/mol Ligand (bar) MeP)

23.2 87886

22.4 93792

22.9 92730

26.0 105206

22.0 87487

21.7 87735

Experimental Test Method Part 1 Ageing

Catalyst solutions were prepared using standard schlenk line techniques.1.45×10⁻⁵ moles Pd₂(dba)₃ and 6 equivalents of the phosphine ligand wereweighed out into a 500 ml round bottom flask using a nitrogen purgeglovebox. The flask was then transferred to a schlenk line. To thisflask was added 172 ml (63.2 wt %) degassed MeP and 116 ml (36.8 wt %)degassed MeOH. To this was added 450 equivalents (420 μl) methanesulphonic acid.

The pre-evacuated autoclave was then charged with the reaction solution.At ambient temperature, 5 bar ethene was added followed by 10 bar 50:50ethene/CO mixture giving a total of 15 bar gas pressure. The stirrer wasthen started (1000 rpm) and the autoclave heated to 80° C. Once at thistemperature the time was noted and the autoclave was left stirring underthese conditions overnight for 17 hours.

The initial solvent composition of 63.2 wt % MeP and 36.8 wt % MeOH wasused so that the consumption of 10 bar ethene/CO would result in theproduction of MeP to yield a new and optimum composition of 70 wt % MeP,30 wt % MeOH ready for the second part of the experiment.

Part 2 Testing

After this time had elapsed, the autoclave total pressure had dropped toaround 5 bar, as the 10 bar of 1:1 ethene/CO had fully reacted. Theautoclave was then heated from 80° C. to 100° C. At this temperatureethene was immediately added to bring the pressure up to 10.2 bar(approx 8 bar of ethylene above solvent vapour pressure at 100° C.). Itwas assumed that all the CO initially present had reacted by this stagemeaning only ethene remained in the autoclave. The reaction wasimmediately initiated by opening the autoclave to a 40 bar 50:50ethene/CO supply resevoir in a 2.251 cylinder via a pressure regulatingvalve (Tescom 1500 model no. 26-1025-24-007) supplied by TescomCorporation set to allow a pressure in the autoclave of 12.2 bar,allowing for a 9:1 ethene/CO ratio to be achieved in the gas phase. Thisreaction was allowed to proceed for 3 hours, after which the autoclavewas cooled and vented.

Part 3 Standard TON Determination

To calculate the average % activity compared with the standard, reactionstandard solutions were prepared in the same way, using standard Schlenkline techniques. In a nitrogen purge glove box, 7.8 mg of Pd₂ dba₃(1.45*10⁻⁵ moles) and 6 equivalents of phosphine ligand (8.7*10⁻⁵moles), where weighed into a 500 ml round bottom flask. The flask wasthen transferred to a Schlenk line. The ligand and palladium were thendissolved in 125 ml of degassed methyl propionate. In order to aidcomplexation, the palladium and ligand were dissolved initially inmethyl propionate and stirred for a period of 45 minutes, beforeaddition of further solvents to the solution. This allows for the insitu formation of a neutral, trigonal planar Pd (O) complex[Pd(ligand)(dba)].

After complexation, 175 ml of methyl propionate/methanol mixture (50% byweight methanol, 50% by weight methyl propionate) was degassed and addedto the flask. Addition of methane sulfonic acid (MSA), 420 μl, completesthe preparation of the catalyst solution. The final composition of thesolution is approximately 70 w't % methylpropionate, 30 wt % methanol.

The catalytic solution was added to the pre-evacuated autoclave andheated to 100 C. The autoclave was then pressured with 8 bars of etheneabove vapour pressure giving a total pressure of 10.2 bars at 100 C.Next the autoclave was pressured to 12.2 bars with addition of CO:ethene(1:1 gas) charged from the 10 litre reservoir. A regulatory valveensures that the pressure of the autoclave is maintained throughout thereaction at 12.2 bars through constant injection of gas from the 10litre reservoir. The pressure of the reservoir as well as the reactortemperature was logged throughout the reaction period of 1 hr.

The moles produced at any point in either reaction are calculated fromthe drop in reservoir pressure by assuming ideal gas behaviour and 100%selectivity for methyl propionate, which allowed reaction TON and rateto be obtained. The results are shown in Tables 1 and 2.

Recycling Examples Experimental

Using standard Schlenk line techniques, reaction solutions were preparedby dissolving 1.45×10⁻⁵ moles of Pd and 8.7×10⁻⁵ moles of ligand in 300ml of solvent consisting of, 70% by weight methyl propionate and 30% byweight methanol. The palladium and ligand were allowed to complex inmethyl propionate, before the methanol was added to the mixture.Addition of 420 μl of methane sulfonic acid (450 equivalents) completedthe preparation of the catalyst solution.

The catalytic solution was added to the pre-evacuated autoclave andheated to 100° C. The autoclave was then pressured with 8 bars of etheneabove vapour pressure giving a total pressure of 10.2 bars at 100° C.Next the autoclave was pressured to 12.2 bars with addition of CO:ethene(1:1 gas) charged from a 10 litre reservoir at higher pressure. Aregulatory valve ensures that the pressure of the autoclave ismaintained throughout the reaction at 12.2 bars through constantinjection of gas from the 10 litre reservoir. The pressure of thereservoir as well as the reactor temperature was logged throughout thereaction period of 3 hrs. The moles produced at any point in thereaction can be calculated from the drop in reservoir pressure byassuming ideal gas behaviour and 100% selectivity for methyl propionate,allowing reaction TON with the particular ligand to be obtained.

After the reaction period, the autoclave was cooled and vented. Thereaction solution was collected from the base of the vessel andimmediately placed under an inert atmosphere. The solution was thenreduced under pressure, to approximately 50 mls. Concentrating thesolution removes the methanol (the most volatile component of themixture) and any traces of CO, both of which can reduce Pd (II) to Pd(O) causing the palladium to precipitate out of solution as metallicpalladium. This concentrated solution, was left to stand overnight underan inert atmosphere and was then used to form the basis of the nextreaction solution with addition of 200 ml of methyl propionate, 100 mlof methanol and 140 μl of methane sulfonic acid (150 equivalents).Excess acid was added to offset a possible loss in acid uponconcentrating of the solution. This recycled material was then added tothe autoclave and reacted under the same set of conditions as before.The catalyst was recycled in this way, until a significant drop inreaction TON was observed. Catalyst recycle was discontinued when theTON dropped below 20000 moles MeP/Mole Pd in a single run.

Recycling Experimental Data

The turnover number (TON) expressed in moles of MeP produced per mole ofpalladium for each recycle experiment is detailed in Table 3. It can beseen that the substituted ferrocene based ligands exhibit enhancedstability over the unsubstituted equivalent.

TABLE 3 TON (moles MeP/Mole Recycle Number Pd) Cumulative TON

Initial Run 90834 90834 Recycle 1 79113 169947 Recycle 2 84796 254743Recycle 3 80001 334744 Recycle 4 71211 405955 Recycle 5 17936 423891

Initial run 84772 84772 Recycle 1 71637 156409 Recycle 2 69118 225527Recycle 3 42847 268374 Recycle 4 14227 282601

Initial Run 90000 90000 Recycle 1 91968 181968 Recycle 2 80355 262323Recycle 3 72307 334630 Recycle 4 57821 392451 Recycle 5 86050 478501Recycle 6 32934 511436 Recycle 7 9534 520969

Std Batch Experiments in 70 wt % MeP, 30 wt % MeOH of Highly SubstitutedLigands Experimental

Reaction solutions were prepared, using standard Schlenk linetechniques. In a nitrogen purge glove box, 7.8 mg of Pd₂ dba₃ (1.45×10⁻⁵moles) and 6 equivalents of phosphine ligand (8.7×10⁻⁵ moles), whereweighed into a 500 ml round bottom flask. The flask was then transferredto a Schlenk line. The ligand and palladium was then dissolved in 125 mlof degassed methyl propionate. In order to aid complexation, thepalladium and ligand were dissolved initially in methyl propionate andstirred for a period of minutes, before addition of further solvents tothe solution. This allows for the in situ formation of a neutral,trigonal planar Pd (O) complex [Pd(ligand)(dba)].

After complexation, 175 ml of methyl propionate/methanol mixture (50% byweight methanol, 50% by weight methyl propionate) was degassed and addedto the flask. Addition of methane sulfonic acid (MSA), 420 μl, completesthe preparation of the catalyst solution.

The catalytic solution was added to the pre-evacuated autoclave andheated to 100° C. The autoclave was then pressured with 8 bars of etheneabove vapour pressure giving a total pressure of 10.2 bars at 100° C.Next the autoclave was pressured to 12.2 bars with addition of CO:ethene(1:1 gas) charged from the 10 litre reservoir. A regulatory valveensures that the pressure of the autoclave is maintained throughout thereaction at 12.2 bars through constant injection of gas from the 10litre reservoir. The pressure of the reservoir as well as the reactortemperature was logged throughout the reaction period of 1 hrs. Themoles produced at any point in the reaction can be calculated from thedrop in reservoir pressure by assuming ideal gas behaviour and 100%selectivity for methyl propionate, allowing reaction TON to be obtained.

TABLE 4 Rate after 1 TON after 1 Maximum Initial rate hour hour

39787 39543 35068

67117 57599 59995

54449 53081 48798

61472 56391 57137

43823 36346 38317

51875 45793 51052

55565 44176 47783

From the above data it can be seen that substitution of thecyclopentadienyl ring at positions on both the top and bottom ringsprovides more active and stable catalysts. In addition, bulkier ligandsand multiply substitued species provide further improvements instability.

The reader's attention is directed to all papers and documents which arefiled concurrently with or previous to this specification in connectionwith this application and which are open to public inspection with thisspecification, and the contents of all such papers and documents areincorporated herein by reference.

All of the features disclosed in this specification (including anyaccompanying claims, abstract and drawings), and/or all of the steps ofany method or process so disclosed, may be combined in any combination,except combinations where at least some of such features and/or stepsare mutually exclusive.

Each feature disclosed in this specification (including any accompanyingclaims, abstract and drawings), may be replaced by alternative featuresserving the same, equivalent or similar purpose, unless expressly statedotherwise. Thus, unless expressly stated otherwise, each featuredisclosed is one example only of a generic series of equivalent orsimilar features.

The invention is not restricted to the details of the foregoingembodiment(s). The invention extends to any novel one, or any novelcombination, of the features disclosed in this specification (includingany accompanying claims, abstract and drawings), or to any novel one, orany novel combination, of the steps of any method or process sodisclosed.

1. A novel bidentate ligand of general formula (I)

wherein: A and B each independently represent a lower alkylene linkinggroup; R represents a hydrocarbyl aromatic structure having at least onearomatic ring to which Q¹ and Q² are each linked, via the respectivelinking group, on available adjacent cyclic atoms of the at least onearomatic ring and which is substituted with one or more substituent(s)Y^(X) on one or more further aromatic cyclic atom(s) of the aromaticstructure; wherein the substituent(s) Y^(X) on the aromatic structurehas a total ^(X=1-n)ΣtY^(X) of atoms other than hydrogen such that^(X=1-n)ΣtY^(X) is 4, where n is the total number of substituent(s)Y^(X) and tY^(X) represents the total number of atoms other thanhydrogen on a particular substituent Y^(X); the groups X¹, X², X³ and X⁴independently represent univalent radicals of up to 30 atoms having atleast one tertiary carbon atom or X¹ and X² and/or X³ and X⁴ togetherform a bivalent radical of up to 40 atoms having at least two tertiarycarbon atoms wherein each said univalent or bivalent radical is joinedvia said at least one or two tertiary carbon atoms respectively to therespective atom Q¹ or Q² and Q¹ and Q² each independently representphosphorus, arsenic or antimony.
 2. A process for the carbonylation ofethylenically unsaturated compounds comprising reacting said compoundwith carbon monoxide in the presence of a source of hydroxyl groups andof a catalyst system, the catalyst system obtainable by combining: (a) ametal of Group 8, 9 or 10 or a compound thereof: and (b) a bidentateligand of general formula (I)

wherein: A and B each independently represent lower alkylene linkinggroups; R represents a hydrocarbyl aromatic structure having at leastone aromatic ring to which Q¹ and Q² are each linked, via the respectivelinking group when the latter is present, on available adjacent cyclicatoms of the at least one aromatic ring and which is substituted withone or more substituent(s) Y^(X) on one or more further aromatic cyclicatom(s) of the aromatic structure; wherein the substituent(s) Y^(X) onthe aromatic structure has a total ^(X=1-nΣtY) ^(X) of atoms other thanhydrogen such that ^(X=1-nΣtY) ^(X) is ≧4, where n is the total numberof substituent(s) Y^(X) and tY^(X) represents the total number of atomsother than hydrogen on a particular substituent Y^(X); the groups X⁻,X², X³ and X⁴ independently represent univalent radicals of up to 30atoms having at least one tertiary carbon atom or X¹ and X² and/or X³and X⁴ together form a bivalent radical of up to 40 atoms having atleast two tertiary carbon atoms wherein each said univalent or bivalentradical is joined via said at least one or two tertiary carbon atomsrespectively to the respective atom Q¹ or Q²; and Q¹ and Q² eachindependently represent phosphorus, arsenic or antimony; and,optionally, a source of anions.
 3. A bidentate ligand or a processaccording to claim 1, wherein each Y^(X) independently represents—SR⁴³R⁴¹R⁴²; wherein S is selected from any one or more of Si, C, N, S,O or aryl; wherein when S is aryl, R⁴⁰, R⁴¹ and R⁴² are independentlyselected from any one or more of hydrogen, alkyl, —BQ³-X³(X⁴) (whereinB, X³ and X⁴ are as defined in claim 1 above and Q³ is defined as Q² orQ² in claim 1 above), phosphorus, aryl, arylene, alkaryl, arylenalkyl,alkenyl, alkynyl, het, hetero, halo, cyano, nitro, —OR¹⁹, —OC(O)R²³,—C(O)R²¹, —C(O) 0R²², —N(R²³)R²⁴, —C(O)N(R²⁸)R²⁶, —SR²⁹, —C(O)SR³⁰,—C(S)N(R²²) R²⁸, —CF₃, —SiR⁷¹R⁷²R⁷³ or alkylphosphorus; wherein when Sis Si, C, N, S or O, R⁴⁰, R⁴¹ and R⁴² are independently selected fromany one or more of hydrogen, alkyl, phosphorus, aryl, arylene, alkaryl,aralkyl, arylenalkyl, alkenyl, alkynyl, het, hetero, halo, cyano, nitro,—OR¹⁹, OC(O)R²³, C(O)R²¹, —C(O)OR²², —N(R²³)R²⁴, —C(O)N(R²⁸) R²⁶, —SR²⁹,—C(O)SR³⁰, —C(S)N(R²⁷)R²⁸, —CF₃, —SiR²¹R²²R²³, or alkylphosphorus,wherein at least one of R⁴⁰-R⁴² is not hydrogen; wherein R¹⁹-R³⁰referred to herein may independently be generally selected fromhydrogen, unsubstituted or substituted aryl or unsubstituted orsubstituted alkyl, and in addition R²¹ may be nitro, halo, amino orthio; and R⁷¹-R⁷³ are defined as R⁴⁰-R⁴² but are preferably C₁-C₄ alkylor phenyl.
 4. The ligand or process as claimed in claim 3, wherein thesubstituents are selected from alkyl, preferably, t-alkyl such as-t-butyl; t-alkyl, aryl such as 2-phenylprop-2-yl; alkylsilyl such as—SiMe₃; -phenyl; alkylphenyl-; phenylalkyl-such as 2-phenylprop-2-yl;phosphinoalkyl—such as phosphinomethyl; or phosphorus; which groups maybe unsubstituted or substituted.
 5. The ligand or process as claimed inclaim 1, wherein there are two or more said Y^(X) substituents
 6. Theligand or process as claimed in claim 5, wherein two or more saidsubstituents combine to form a further ring structure.
 7. The ligand orprocess as claimed in claim 1, wherein the hydrocarbyl aromaticstructure has from 6 up to 30 cyclic atoms.
 8. The ligand or process asclaimed in claim 1, wherein the hydrocarbyl aromatic structureR(Y^(X))_(n) is selected from 4 and/or 5 t-alkylbenzene-1,2-diyl,4,5-diphenyl-benzene-1,2-diyl, 4 and/or 5-phenyl-benzene-1,2-diyl,4,5-di-t-butyl-benzene-1,2-diyl, 4 or 5-t-butylbenzene-1,2-diyl, 2, 3, 4and/or 5 t-alkyl-naphthalene-8,9-diyl, 1H-inden-5,6-diyl, 1, 2 and/or 3methyl-1H-inden-5,6-diyl, 4,7 methano-1H-indene-1,2-diyl, 1, 2 and/or3-dimethyl-1H-inden 5,6-diyls,1,3-bis(trimethylsilyl)-isobenzofuran-5,6-diyl,4-(trimethylsilyl)benzene-1,2 diyl, 4-phosphinomethyl benzene-1,2 diyl,4-(2′-phenylprop-2′-yl) benzene-1,2 diyl,4-dimethylsilylbenzene-1,2diyl, 4-di-t-butyl,methylsilylbutyldimethylsilyl)-benzene-1,2diyl, benzene-1,2diyl,4-(t-4-t-butylsilyl-benzene-1,2diyl,4-(tri-t-butylsilyl)-benzene-1,2diyl,4-(2′-tert-butylprop-2′-yl)benzene-1,2 diyl, 4-(2′,2′,3′,4′,4′pentamethyl-pent-3′-yl)-benzene-1,2diyl,4-(2′,2′,4′,4′-tetramethyl,3′-t-butyl-pent-3′-yl)-benzene-1,2 diyl,4-(or 1′)t-alkylferrocene-1,2-diyl, 4,5-diphenyl-ferrocene-1,2-diyl,4-(or 1′)phenyl-ferrocene-1,2-diyl, 4,5-di-t-butyl-ferrocene-1,2-diyl,4-(or 1′)t-butylferrocene-1,2-diyl, 4-(or 1′)(trimethylsilyl)ferrocene-1,2 diyl, 4-(or 1′)phosphinomethyl ferrocene-1,2 diyl, 4-(or1′)(2′-phenylprop-2′-yl) ferrocene-1,2 diyl, 4-(or1′)dimethylsilylferrocene-1,2diyl, 4-(or 1′)di-t-butyl,methylsilylferrocene-1,2diyl, 4-(or 1′)(t-butyldimethylsilyl)-ferrocene-1,2diyl,4-(or 1′)t-butylsilyl-ferrocene-1,2diyl, 4-(or1′)(tri-t-butylsilyl)-ferrocene-1,2diyl, 4-(or1′)(2′-tert-butylprop-2′-yl)ferrocene-1,2 diyl, 4-(or 1′)(2′,2′,3′,4′,4′pentamethyl-pent-3′-yl)-ferrocene-1,2diyl, 4-(or1′)(2′,2′,4′,4′-tetramethyl,3′-t-butyl-pent-3′-yl)-ferrocene-1,2 diyl,1′,2′,3′-triphenyl ferrocene-1,2-diyl, 1′,2′,3′,4′-tetramethylferrocene-1,2-diyl, 1′,2′,3′,4′-tetraphenyl ferrocene-1,2-diyl,1′,2′,3′,4′,5′-pentamethyl ferrocene-1,2-diyl, or1′,2′,3′,4′,5′-pentaphenyl ferrocene-1,2-diyl.
 9. The ligand or processas claimed in claim 1, wherein each Y^(X) and/or combination of two ormore Y^(X) groups is at least as sterically hindering as phenyl, morepreferably, t-butyl.
 10. The ligand or process as claimed in claim 1,wherein the group X¹ represents CR¹ (R²) (R³) X² represents CR⁴ (R⁵)(R⁶) X³ represents CR⁷(R⁸) (R⁹) and X⁴ represents CR¹⁰(R)(R), wherein R¹to R¹² represent alkyl, aryl or het.
 11. The ligand or process asclaimed in claim 1, wherein the organic groups R¹-R³, R⁴-R⁶, R⁷-R⁹and/or R¹⁰-R¹² or, alternatively, R¹-R⁶ and/or R⁷-R¹² when associatedwith their respective tertiary carbon atom(s) form composite groupswhich are at least as sterically hindering as t-butyl(s).
 12. The ligandor process as claimed in claim 1, wherein when cyclic, X¹, X², X³ and/orX⁴ represent congressyl, norbornyl 1-norbornadienyl or adamantyl. 13.The ligand or process as claimed in claim 1, wherein X¹ and X² togetherwith Q² to which they are attached form an optionally substituted2-Q²-tricyclo[3.3.1.1{3,7}]decyl group or derivative thereof, or X¹ andX² together with Q² to which they are attached form a ring system offormula 1a


14. The ligand or process as claimed in claim 1, wherein X³ and X⁴together with Q¹ to which they are attached may form an optionallysubstituted 2-Q¹-tricyclo[3.3.1.1{3,7}]decyl group or derivativethereof, or X³ and X⁴ together with Q¹ to which they are attached form aring system of formula 1b


15. The ligand or process as claimed in claim 1, wherein suitablebidentate ligands are 1,2-bis(di-t-butylphosphinomethyl)-4,5-diphenylbenzene; 1,2-bis(di-t-butylphosphinomethyl)-4-phenylbenzene;1,2-bis(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1,2-bis(di-t-butylphosphinomethyl)-4-(trimethylsilyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-diphenylbenzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-phenylbenzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-bis-(trimethylsilyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-(trimethylsilyl)benzene;1,2-bis(di-adamantylphosphinomethyl)-4,5 diphenylbenzene;1,2-bis(di-adamantylphosphinomethyl)-4-phenyl benzene;1,2-bis(di-adamantylphosphinomethyl)-4,5 bis-(trimethylsilyl)benzene;1,2-bis(di-adamantylphosphinomethyl)-4-(trimethylsilyl) benzene; 1-(P,Padamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-diphenylbenzene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-phenylbenzene; 1-(P,Padamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl) 2(di-t-butylphosphinomethyl)-4,5-diphenylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-phenylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-phenylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(trimethylsilyl)benzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylbenzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-phenylbenzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(trimethylsilyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-diphenylbenzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-phenylbenzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-bis-(trimethylsilyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-diphenylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-phenylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-phenylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(trimethylsilyl)benzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-diphenylbenzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-phenylbenzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-bis-(trimethylsilyl)benzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(trimethylsilyl)benzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-diphenylbenzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-phenylbenzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-bis-(trimethylsilyl)benzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(trimethylsilyl)benzene;1,2-bis(di-t-butylphosphinomethyl)-4,5-di-(2′ phenylprop-2′-yl)benzene;1,2-bis(di-t-butylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1,2-bis(di-t-butylphosphinomethyl)-4,5-di-t-butyl benzene;1,2-bis(di-t-butylphosphinomethyl)-4-t-butylbenzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-2′-phenylprop-2′-ylbenzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-(di-t-butyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-t-butylbenzene;1,2-bis(di-adamantylphosphinomethyl)-4,5 di-(2′phenylprop-2′-yl)benzene;1,2-bis(di-adamantylphosphinomethyl)-4-(2′-phenylprop-2′-yl) benzene;1,2-bis(di-adamantylphosphinomethyl)-4,5-di-t-butylbenzene;1,2-bis(di-adamantylphosphinomethyl)-4-t-butyl benzene; 1-(P,Padamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′phenylprop-2′-yl)benzene; 1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-di-t-butylbenzene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-t-butylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-1-(di-t-butylphosphinomethyl)-4,5-di-t-butylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-t-butylbenzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)benzene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-t-butylbenzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)benzene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-t-butylbenzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(2′-phenylprop-2′-yl)benzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-(di-t-butyl)benzene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-t-butylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-(di-t-butyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-t-butylbenzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(2′-phenylprop-2′-yl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)benzene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-t-butylbenzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(2′-phenylprop-2′-yl)benzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-(di-t-butyl)benzene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-t-butylbenzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-di-(2′-phenylprop-2′-yl)benzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(2′-phenylprop-2′-yl)benzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-(di-t-butyl)benzene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-t-butylbenzene, 1,2-bis(di-t-butylphosphinomethyl)-4,5-diphenyl ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4-(or 1′)phenylferrocene;1,2-bis(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl) ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4-(or 1′)(trimethylsilyl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-diphenylferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-(or1′)phenylferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-bis-(trimethylsilyl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-(or1′)(trimethylsilyl)ferrocene; 1,2-bis(di-adamantylphosphinomethyl)-4,5diphenylferrocene; 1,2-bis(di-adamantylphosphinomethyl)-4-(or 1′)phenylferrocene; 1,2-bis(di-adamantylphosphinomethyl)-4,5bis-(trimethylsilyl)ferrocene;1,2-bis(di-adamantylphosphinomethyl)-4-(or 1′)(trimethylsilyl)ferrocene; 1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-diphenylferrocene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(or 1′)phenylferrocene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)(trimethylsilyl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-diphenylferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)phenyl ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)(trimethylsilyl) ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(or1′)phenyl ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(trimethylsilyl) ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(or1′)phenyl ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(trimethylsilyl) ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-diphenylferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(or1′)phenyl ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-bis-(trimethylsilyl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(or1′)(trimethylsilyl) ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-diphenylferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)phenyl ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)(trimethylsilyl) ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-diphenylferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(or1′)phenyl ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-bis-(trimethylsilyl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(trimethylsilyl) ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-diphenylferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)phenyl ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-bis-(trimethylsilyl)ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)(trimethylsilyl) ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-diphenylferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)phenyl ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-bis-(trimethylsilyl)ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)(trimethylsilyl) ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl)ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4,5-di-t-butyl ferrocene;1,2-bis(di-t-butylphosphinomethyl)-4-(or 1′)_(t)-butylferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-(or1′)(2′-phenylprop-2′-yl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4,5-(di-t-butyl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-4-(or1′)t-butylferrocene;1,2-bis(di-adamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene; 1,2-bis(di-adamantylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1,2-bis(di-adamantylphosphinomethyl)-4,5-(di-t-butyl) ferrocene;1,2-bis(di-adamantylphosphinomethyl)-4-(or 1′)t-butyl ferrocene; 1-(P,Padamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl)ferrocene; 1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(P,P adamantyl, t-butylphosphinomethyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)t-butylferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)t-butyl ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxa-adamantyl)-2-(diadamantylphosphinomethyl)-4-(or1′)t-butyl ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(di-t-butylphosphinomethyl)-2-(diadamantylphosphinomethyl)-4-(or1′)t-butyl ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4,5-(di-t-butyl)ferrocene;1,2-bis(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-4-(or1′)t-butyl ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(di-t-butylphosphinomethyl)-4-(or1′)t-butyl ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4,5-(di-t-butyl)ferrocene;1-(2-phosphinomethyl-1,3,5-trimethyl-6,9,10-trioxatricyclo-{3.3.1.1[3.7]}decyl)-2-(diadamantylphosphinomethyl)-4-(or1′)_(t)-butyl ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}-decyl)-4,5-(di-t-butyl)ferrocene;1,2-bis-perfluoro(2-phosphinomethyl-1,3,5,7-tetramethyl-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)_(t)-butyl ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-di-(2′-phenylprop-2′-yl)ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)(2′-phenylprop-2′-yl) ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4,5-(di-t-butyl)ferrocene;1,2-bis-(2-phosphinomethyl-1,3,5,7-tetra(trifluoro-methyl)-6,9,10-trioxatricyclo{3.3.1.1[3.7]}decyl)-4-(or1′)t-butyl ferrocene or any of the above ligands wherein one of themethylene groups representing group A or group B is removed so that oneof the respective phosphorus atoms is joined directly to the ferroceneor benzene ring representing group R thus forming a C₃ bridge connectingthe two phosphorus atoms representing Q₁ and Q₂.
 16. The process asclaimed in claim claim 1, wherein the ethylenically unsaturatedcompounds are ethylenically unsaturated compounds having from 2 to 50carbon atoms per molecule, or mixtures thereof.
 17. The ligand orprocess as claimed in claim 1, wherein the ethylenically unsaturatedcompounds are selected from acetylene, methyl acetylene, propylacetylene, 1,3-butadiene, ethylene, propylene, butylene, isobutylene,pentenes, pentene nitriles, alkyl pentenoates such as methyl3-pentenoates, pentene acids (such as 2- and 3-pentenoic acid),heptenes, vinyl esters such as vinyl acetate, octenes, dodecenes.
 18. Acatalyst system obtainable by combining (a) a metal of Group 8, 9 or 10or a compound thereof: and (b) a bidentate ligand of general formula (I)

wherein: A and B each independently represent lower alkylene linkinggroups; R represents a hydrocarbyl aromatic structure having at leastone aromatic ring to which Q¹ and Q² are each linked, via the respectivelinking group, on available adjacent cyclic atoms of the at least onearomatic ring and which is substituted with one or more substituent(s)Y^(X) on one or more further aromatic cyclic atom(s) of the aromaticstructure; wherein the substituent(s) Y^(X) on the aromatic structurehas a total ^(X=1-n)ΣtY^(X) of atoms other than hydrogen such that^(X=1-n)ΣtY^(X) is ≧4, where n is the total number of substituent(s)Y^(X) and tY^(X) represents the total number of atoms other thanhydrogen on a particular substituent Y^(X); the groups X⁻, X², X³ and X⁴independently represent univalent radicals of up to 30 atoms having atleast one tertiary carbon atom or X¹ and X² and/or X³ and X⁴ togetherform a bivalent radical of up to 40 atoms having at least two tertiarycarbon atoms wherein each said univalent or bivalent radical is joinedvia said at least one or two tertiary carbon atoms respectively to therespective atom Q¹ or Q²; and Q¹ and Q² each independently representphosphorus, arsenic or antimony; and, optionally, a source of anions.19. (canceled)
 20. (canceled)
 21. (canceled)
 22. A bidentate ligand,process or catalyst system according to claim 1 wherein the ligands offormula 1are selected from:—

1,2-bis(di-tert-butylphosphinomethyl)-3,6-diphenyl-4,5-dimethylbenzene

1,2 bis(di-tert-butyl(phosphinomethyl)-4,5-diphenyl benzene

1,2-bis(di-tert-butylphospinomethyl)-1′-trimethylsilyl ferrocene

1,2-bis(di-tert-butylphospinomethyl)-1′-tert-butyl ferrocene

5,6-bis(di-tert-butylphosphinomethyl)-1,3-bis-trimethylsilyl-1,3-dihydroisobenzofuran

1,2bis(di-tert-butylphosphinomethyl)-3,6-diphenyl benzene

1,2-bis(di-tert-butylphospinomethyl)-4trimethylsilyl ferrocene

1,2-bis(di-tert-butyl(phosphinomethyl))-4,5-di(4′-tert butylphenyl)benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4-trimethylsilyl benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4-(tert-butyldimethylsilyl)benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4,5-bis(trimethylsilyl)benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4-tert-butyl benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4,5-di-tert-butyl benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4-(tri-tert-butylmethyl)benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4-(tri-tert-butylsilyl)benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4-(2′-phenylprop-2′-yl)benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4-phenyl benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-3,6-dimethyl-4,5-diphenylbenzene

1,2-bis(di-tert-butyl(phosphinomethyl))-3,4,5,6-tetraphenyl benzene

4-(1-[3,4-Bis-tert-butyl-phosphanyl)-methyl]-phenyl}1-methyl-ethyl)-benzoylchloride

1,2-bis(di-tert-butyl(phosphinomethyl)-4-(4′-chlorocarbonyl-phenyl)benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4-(phosphinomethyl)benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4-(2′-naphthylprop-2′-yl)benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4-(3′,4′-bis(di-tert-butyl(phosphinomethyl))phenyl)benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-3-(2′,3′-bis(di-tert-butyl(phosphinomethyl))phenyl)benzene

1,2-bis(di-tert-butyl(phosphinomethyl))-4-tertbutyl-5-(2′-tertbutyl-4′,5′-bis(di-tert-butyl(phosphinomethyl))phenyl)benzene;or selected from any one of the above structures wherein one or more ofthe X¹-X⁴ tertiary carbon bearing groups, t-butyl, attached to the Q¹and/or Q² group phosphorus is replaced by a suitable alternativeselected from adamantyl, 1,3 dimethyl adamantyl, congressyl, norbornylor 1-norbornodienyl, or X′ and X² together and/or X³ and X⁴ togetherform together with the phosphorus a 2-phospha-tricyclo[3.3.1.1{3,7}decyl group such as 2-phospha-1,3,5,7-tetramethyl-6,9,10-trioxadamantylor 2-phospha-1,3,5-trimethyl-6,9,10-trioxadamantyl; or selected from anyone of the above structures or alternative structures wherein one of themethylene linking groups representing A or B in formula 1is removed sothat the respective phosphorus atom is attached directly to the aromaticring representing R and so that a C₃ bridge connects two phosphorusatoms representing Q¹ and Q² in the example structures.
 23. A processaccording to claim 2, wherein the metal of Group 8, 9 or 10 or acompound thereof is palladium.